[Federal Register Volume 78, Number 192 (Thursday, October 3, 2013)]
[Proposed Rules]
[Pages 61273-61293]
From the Federal Register Online via the Government Printing Office [www.gpo.gov]
[FR Doc No: 2013-24173]
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DEPARTMENT OF THE INTERIOR
Fish and Wildlife Service
50 CFR Part 17
[Docket No. FWS-R4-ES-2013-0033; 4500030113]
RIN 1018-AZ15
Endangered and Threatened Wildlife and Plants; Proposed
Endangered Status for Brickellia mosieri (Florida Brickell-bush) and
Linum carteri var. carteri (Carter's Small-flowered Flax)
AGENCY: Fish and Wildlife Service, Interior.
ACTION: Proposed rule.
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SUMMARY: We, the U.S. Fish and Wildlife Service (Service), propose to
list Brickellia mosieri (Florida brickell-bush) and Linum carteri var.
carteri (Carter's small-flowered flax), as endangered species under the
Endangered Species Act. If we finalize this rule as proposed, it would
extend the Act's protections to these plants.
DATES: We will accept comments received or postmarked on or before
December 2, 2013. Comments submitted electronically using the Federal
eRulemaking Portal (see ADDRESSES section, below) must be received by
11:59 p.m. Eastern Time on the closing date. We must receive requests
for public hearings, in writing, at the address shown in FOR FURTHER
INFORMATION CONTACT by November 18, 2013.
ADDRESSES: You may submit comments by one of the following methods:
(1) Electronically: Go to the Federal eRulemaking Portal: http://www.regulations.gov. In the search box, enter FWS-R4-ES-2013-0033,
which is the docket number for this rulemaking. You may submit a
comment by clicking on ``Comment Now!'' If your comments will fit in
the comment box provided, please use this feature of http://www.regulations.gov, as it is most compatible with our comment review
procedures. If you attach your comments as a separate document, our
preferred file format is Microsoft Word. If you attach multiple
comments (such as form letters), our preferred format is a spreadsheet
in Microsoft Excel.
(2) By hard copy: Submit by U.S. mail or hand-delivery to: Public
Comments Processing, Attn: FWS-R4-ES-2013-0033; Division of Policy and
Directives Management; U.S. Fish and Wildlife Service; 4401 N. Fairfax
Drive, MS 2042-PDM; Arlington, VA 22203.
We request that you send comments only by the methods described
above. We will post all information received on http://www.regulations.gov. This generally means that we will post any
personal information you provide us (see the Information Requested
section below for more information).
FOR FURTHER INFORMATION CONTACT: Larry Williams, Field Supervisor, U.S.
Fish and Wildlife Service, South Florida Ecological Services Office,
1339 20th Street, Vero Beach, FL 32960, by telephone 772-562-3909, or
by facsimile 772-562-4288. Persons who use a telecommunications device
for the deaf (TDD) may call the Federal Information Relay Service
(FIRS) at 800-877-8339.
SUPPLEMENTARY INFORMATION:
Executive Summary
Why we need to publish a rule. Under the Act, if we intend to list
a species as endangered or threatened throughout all or a significant
portion of its range, we are required to promptly publish a proposal in
the Federal Register and make a final determination on our proposal
within one year. Listing a species as an endangered or threatened
[[Page 61274]]
species can only be completed by issuing a rule.
This document consists of a proposed rule to list Brickellia
mosieri and Linum carteri var. carteri as endangered species. Elsewhere
in today's Federal Register, we propose to designate critical habitat
for Brickellia mosieri and Linum carteri var. carteri under the Act.
Both plants are candidate taxa (i.e., species or varieties) for which
we have on file sufficient information on biological vulnerability and
threats to support preparation of a listing proposal, but for which
development of a listing regulation has been precluded by other higher
priority listing activities. This rule reassesses all available
information regarding status of and threats to both plants.
The basis for our action. Under the Act, we may determine that a
species is an endangered or threatened species based on any of five
factors: (A) The present or threatened destruction, modification, or
curtailment of its habitat or range; (B) overutilization for
commercial, recreational, scientific, or educational purposes; (C)
disease or predation; (D) the inadequacy of existing regulatory
mechanisms; or (E) other natural or manmade factors affecting its
continued existence. We have determined that the threats to both
Brickellia mosieri and Linum carteri var. carteri consist primarily of
habitat loss and modification through urban and agricultural
development, and lack of adequate fire management (Factor A);
proliferation of nonnative invasive plants, and sea level rise (Factor
E); and these threats are not reduced by existing regulatory mechanisms
(Factor D).
We will seek peer review. We are seeking comments from
knowledgeable individuals with scientific expertise to review our
analysis of the best available science and application of that science
and to provide any additional scientific information to improve this
proposed rule. Because we will consider all comments and information
received during the comment period, our final determinations may differ
from this proposal.
Information Requested
We intend that any final action resulting from this proposed rule
will be based on the best scientific and commercial data available and
be as accurate and as effective as possible. Therefore, we request
comments or information from the public, other concerned governmental
agencies, Native American tribes, the scientific community, industry,
or any other interested parties concerning this proposed rule. We
particularly seek comments concerning:
(1) Both plants' biology, range, and population trends, including:
(a) Habitat requirements for feeding, breeding, and sheltering;
(b) Genetics and taxonomy;
(c) Historical and current range including distribution patterns;
(d) Historical and current population levels, and current and
projected trends; and
(e) Past and ongoing conservation measures for the plants, their
habitat, or both.
(2) The factors that are the basis for making a listing
determination for a species under section 4(a) of the Act (16 U.S.C.
1531 et seq.), which are:
(a) The present or threatened destruction, modification, or
curtailment of their habitat or range;
(b) Overutilization for commercial, recreational, scientific, or
educational purposes;
(c) Disease or predation;
(d) The inadequacy of existing regulatory mechanisms; or
(e) Other natural or manmade factors affecting their continued
existence.
(3) Biological, commercial trade, or other relevant data concerning
any threats (or lack thereof) to these plants and regulations that may
be addressing those threats.
(4) Additional information concerning the historical and current
status, range, distribution, and population size of these plants,
including the locations of any additional populations of these plants.
(5) Current or planned activities in the areas occupied by these
plants and possible impacts of these activities on these plants.
(6) Additional information concerning the biological or ecological
requirements of these plants, including pollination and pollinators.
Please note that submissions merely stating support for or
opposition to the action under consideration without providing
supporting information, although noted, will not be considered in
making a determination, as section 4(b)(1)(A) of the Act directs that
determinations as to whether any species is an endangered or threatened
species must be made ``solely on the basis of the best scientific and
commercial data available.''
You may submit your comments and materials concerning this proposed
rule by one of the methods listed in ADDRESSES. We request that you
send comments only by the methods described in ADDRESSES.
If you submit information via http://www.regulations.gov, your
entire submission--including any personal identifying information--will
be posted on the Web site. If your submission is made via a hardcopy
that includes personal identifying information, you may request at the
top of your document that we withhold this information from public
review. However, we cannot guarantee that we will be able to do so. We
will post all hardcopy submissions on http://www.regulations.gov.
Please include sufficient information with your comments to allow us to
verify any scientific or commercial information you include.
Comments and materials we receive, as well as supporting
documentation we used in preparing this proposed rule, will be
available for public inspection on http://www.regulations.gov, or by
appointment, during normal business hours, at the U.S. Fish and
Wildlife Service, South Florida Ecological Services Office (see FOR
FURTHER INFORMATION CONTACT).
Previous Federal Actions
Brickellia mosieri was first recognized as a candidate for possible
future listing on September 27, 1985 (50 FR 39526), and we assigned the
species a listing priority number (LPN) of 2. Candidate species are
assigned LPNs based on immediacy and magnitude of threats, as well as
taxonomic status. The lower the LPN, the higher priority that species
is for us to determine appropriate action using our available resources
(September 21, 1983; 48 FR 43100). Category 2 candidates were those
taxa for which information contained in our files indicated that
listing may be appropriate, but for which additional data were needed
to support a listing proposal.
Linum carteri var. carteri was also first recognized as a candidate
for possible future listing on September 27, 1985 (50 FR 39526), and
assigned an LPN of 1. Category 1 candidates were those taxa for which
the Service had substantial information on biological vulnerability and
threats to support the appropriateness of proposing to list them as
endangered or threatened species. On February 21, 1990, we downgraded
this variety to a category 2 candidate (55 FR 6184).
Both Brickellia mosieri and Linum carteri var. carteri remained on
the candidate list as published in what is now known as the Candidate
Notice of Review (CNOR) until 1993 (55 FR 6184, February 21, 1990; 58
FR 51144, September 30, 1993). Both plants were removed from the
candidate list from 1996 to 1998 because there was not sufficient
information on their biological vulnerability and threats to
[[Page 61275]]
support issuance of a proposed rule. Both plants were again placed on
the candidate list in the 1999 CNOR (October 25, 1999, 64 FR 57534), in
which we determined that listing was warranted, but was precluded due
to workloads and priorities. B. mosieri was assigned an LPN of 5,
meaning that the magnitude of threats for the species remained high but
were not imminent. L. c. var. carteri was assigned an LPN of 3, meaning
that the magnitude of threats remained both high and immediate and
reflected its taxonomic status at the varietal level.
Both plants remained on the candidate list as published in the
CNORs from 2001 to 2004 (66 FR 54808, October 30, 2001; 67 FR 40657,
June 13, 2002; 69 FR 24876, May 4, 2004). On May 11, 2005, we published
findings for both plants in the 2005 CNOR (70 FR 24869) in response to
a petition received on May 11, 2004. Brickellia mosieri remained on the
candidate list, but we changed the LPN from a 5 to an 8, meaning that
the magnitude of threats to the species were moderate, but immediate
(70 FR 24869). A primary factor noted in this downgrading was the
occurrence of 13 of the 17 known populations on conservation lands,
which were being managed appropriately with prescribed fire and control
of invasive nonnative species. Linum carteri var. carteri also remained
on the candidate list, with an unchanged LPN of 3 (70 FR 24869). B.
mosieri and L. c. var. carteri remained on the candidate list as
published in the CNORs from 2006 to 2012, with LPNs of 8 and 3,
respectively (71 FR 53756, September 12, 2006; 72 FR 69034, December 6,
2007; 73 FR 75176, December 10, 2008; 74 FR 57804, November 9, 2009; 75
FR 69222, November 10, 2010; 76 FR 66370, October 26, 2011; and 77 FR
69994, November 21, 2012).
On May 10, 2011, as part of an agreement with one of the agency's
most frequent plaintiffs, the Service filed a workplan with the U.S.
District Court for the District of Columbia. The workplan will enable
the agency to, over a period of 6 years, systematically review and
address the needs of more than 250 species listed within the 2010 CNOR,
including Brickellia mosieri and Linum carteri var. carteri, to
determine if these plants should be added to the Federal Lists of
Endangered and Threatened Wildlife and Plants. This workplan will
enable the Service to again prioritize its workload based on the needs
of candidate species, while also providing state wildlife agencies,
stakeholders, and other partners clarity and certainty about when
listing determinations will be made. On July 12, 2011, the Service
reached an agreement with another frequent plaintiff group and further
strengthened the workplan, which will allow the agency to focus its
resources on the species most in need of protection under the Act.
These agreements were approved by the court on September 9, 2011.
Status Assessment for Brickellia mosieri and Linum carteri var. carteri
Background
It is our intent to discuss below only those topics directly
relevant to the listing of Brickellia mosieri and Linum carteri var.
carteri as endangered in this proposed rule.
Brickellia mosieri
Description
Brickellia mosieri (Family: Asteraceae) is a perennial herb. Mature
plants are 0.3-1.1 meters (m) (1.0-3.5 feet (ft)) tall, slender, erect,
and branching (Chafin 2000, page numbers not applicable). Leaves are 1-
3 centimeters (cm) (0.4-1.2 inches (in)) long, alternate, narrow,
linear, thick, usually spreading or curved downward, entire or slightly
toothed, and resin-dotted (Chafin 2000, page numbers not applicable).
The flower heads are in loose, open clusters at the ends of branches
(Chafin 2000, page numbers not applicable). Disk flowers are white in
small, dense heads surrounded by hairy, slightly ribbed bracts; there
are no ray flowers, although long-style branches (white, sometimes
brown) may appear to be rays (Chafin 2000, page numbers not
applicable).
Taxonomy
Brickellia mosieri was first described by Small in 1933 as Kuhnia
mosieri (Bradley and Gann 1999, p. 11). In 1970, Long called the
species Kuhnia eupatorioides var. floridana, reducing it to a variety
of a more widespread species occurring in the eastern United States
(Bradley and Gann 1999, p. 11). In 1971, Shinners included all members
of the genus Kuhnia in Brickellia and restored the plant to species
status, calling it Brickellia mosieri (Bradley and Gann 1999, p. 11).
In a 1989 study of the Brickellia eupatorioides complex, Turner
identified it as a variety of the more widespread Brickellia
eupatorioides, and gave it the new name Brickellia eupatorioides var.
floridana. Wunderlin and Hansen (2003, pp. 300-301) recognized
Brickellia mosieri, thinking the plant to be specifically distinct from
Brickellia eupatorioides (Bradley and Gann 1999, p. 11) and
differentiating the species by leaf width and margin (i.e., B. mosieri
having 1-3 millimeter (mm) (0.04-0.12 in) wide, entire or obscurely
toothed leaves versus B. eupatorioides having 5-40 mm (0.2-1.6 in)
wide, coarsely toothed leaves).
While some sources (Integrated Taxonomic Information System (ITIS)
2013a, page numbers not applicable) indicate that Brickellia
eupatorioides var. floridana is the accepted taxonomy, local sources
including the online Atlas of Florida Vascular Plants (Wunderlin and
Hansen 2008, page numbers not applicable), the Florida Department of
Agriculture and Consumer Services (FDACS; Coile and Garland 2003, p.
7), and the Institute for Regional Conservation (IRC) all use
Brickellia mosieri. Although there is not complete agreement on whether
this taxon is a variety or a species, there is consensus that it is a
distinct taxon. Based upon the best available scientific information,
Brickellia mosieri is a distinct taxon, endemic to Miami-Dade County in
Florida. Synonyms include Brickellia eupatorioides var. floridana,
Kuhnia eupatorioides var. floridana, and Kuhnia mosieri (Wunderlin and
Hansen 2008, page numbers not applicable).
Climate
The climate of south Florida where Brickellia mosieri occurs is
classified as tropical savanna and is characterized by distinct wet and
dry seasons and a monthly mean temperature above 18 degrees Celsius
([deg]C) (64.4 degrees Fahrenheit ([deg]F)) in every month of the year
(Gabler et al. 1994, p. 211). Freezes can occur in the winter months,
but are infrequent at this latitude in south Florida. Rainfall in the
pine rockland community where B. mosieri occurs exclusively, varies
from an annual average of 153-165 cm (60-65 in) in the northern portion
of the Miami Rock Ridge to an average of 140-153 cm (55-60 in) in the
southern portion (Snyder et al. 1990, p. 238). Approximately 75 percent
of yearly rainfall occurs during the wet season from June through
September (Snyder et al. 1990, p. 238).
Habitat
Brickellia mosieri grows exclusively on the Miami Rock Ridge in
Miami-Dade County outside the boundaries of Everglades National Park
(ENP). This area extends from the ENP boundary, near the Park entrance
road, northeast approximately 72 kilometers (km) (45 miles (mi)) to its
end near North Miami. Habitat conditions more specific to this area are
highlighted below. The pine rocklands are a unique ecosystem found
[[Page 61276]]
on limestone substrates in three areas in Florida--the Miami Rock
Ridge, in the Florida Keys, and in the Big Cypress Swamp. The pine
rocklands differ to some degree between and within these areas with
regard to substrate (e.g., amount of exposed limestone, type of soil),
elevation, hydrology, and species composition (both plant and animal).
Pine rockland occurs on relatively flat terrain, approximately 2-7
m (6.5-23.0 ft) above sea level with an average elevation of
approximately 3 m (9.8 ft) (Service 1999, p. 3-167; Florida Natural
Areas Inventory (FNAI) 2010, p. 62). On the Miami Rock Ridge, oolitic
limestone is at or very near the surface, and solution holes
occasionally form where the surface limestone is dissolved by organic
acids. There is typically very little soil development, consisting
primarily of accumulations of low-nutrient sand, marl, clayey loam, and
organic debris found in solution holes, depressions, and crevices on
the limestone surface (FNAI 2010, p. 62). However, extensive sandy
pockets can be found at the northern end of the Miami Rock Ridge,
beginning from approximately North Miami Beach and extending south to
approximately SW. 216 Street (which runs east-west approximately one-
half mile south of Quail Roost Pineland) (Service 1999, p. 3-162).
Brickellia mosieri tends to occur on exposed limestone with minimal
organic litter and in areas with only minor amounts of substrate
disturbance (Bradley and Gann 1999, p. 11).
Pine rocklands are generally moderately to well drained, depending
on the porosity of the limestone substrate and landscape position,
including nearby associated natural communities. In pine rocklands on
the Miami Rock Ridge outside of ENP, the water table seldom reaches the
surface (Service 1999, p. 3-167). Bradley and Gann (1999) found one
occurrence of Brickellia mosieri in a low-elevation pine rockland (2-3
m above sea level) very close to a marl prairie. The pine rockland that
contains this occurrence may have flooded periodically during the
summer wet season. Known populations of B. mosieri are found at
elevations ranging from approximately 1.7-4.8 m (5.5-15.8 ft). While
species occurrences are distributed throughout this range, there are
two elevational groupings in the landscape--one with average elevations
of approximately 1.7-2.1 m (5.5-7.0 ft) and the other, larger grouping
between approximately 2.7 and 4.0 m (9.0 and 13.0 ft).
Pine rockland is characterized by an open canopy of South Florida
slash pine (Pinus elliottii var. densa). Subcanopy development is rare
in well-maintained pine rocklands, with only occasional hardwoods such
as Lysiloma bahamensis (wild tamarind) and Quercus virginiana (live
oak) growing to tree size in Miami Rock Ridge pinelands (Snyder et al.
1990, p. 253). The shrub/understory layer is a diverse mix of species
including both temperate and tropical shrubs and palms. Dominant plants
in the shrub layer of pine rocklands vary based on elevation, soils,
and location, including nearby associated natural communities. The pine
rocklands where Brickellia mosieri occurs are characterized by an open
shrub canopy of Serenoa repens (saw palmetto), Myrica cerifera (wax
myrtle), Metopium toxiferum (poisonwood), and Sideroxylon salicifolium
(willow bustic) as well as species with more restricted distribution
within pine rocklands including Sideroxylon reclinatum (buckthorn),
Callicarpa americana (beauty berry), Dodonaea angustifolia (varnish
leaf), and Ilex cassine (dahoon holly) (Snyder et al. 1990, p. 254;
Bradley and Gann 1999, p. 12). The shrub layer in pinelands occurring
in the northern end of the Miami Rock Ridge more closely resembles pine
flatwoods as a result of the amount of sandy soils in this area, with
species such as Lyonia fruticosa (staggerbush), Quercus minima (dwarf
live oak), Quercus pumila (running oak), and Vaccinium myrsinites
(shiny blueberry) becoming more common (Snyder et al. 1990, p. 255).
The height and density of the shrub layer vary based on fire frequency,
with understory plants growing taller and more dense as time since fire
increases.
Pine rocklands in all three areas of Florida also boast a richly
diverse herbaceous layer, including a large number of rare and endemic
species such as Brickellia mosieri. The diversity of the herbaceous
layer decreases as the density of the shrub layer increases (i.e., as
understory openness decreases), and pine rockland on the mainland has a
more diverse herbaceous layer due to the presence of temperate species
and some tropical species that do not occur in the Florida Keys (FNAI
2010, p. 63). The herbaceous layer can range from mostly continuous in
areas with more soil development and little exposed limestone, to
sparse where much of the limestone is at the surface. Most herbaceous
species in pine rocklands are perennials (Snyder et al. 1990, p. 257).
Common herbaceous associates of B. mosieri in the Miami Rock Ridge pine
rocklands include Schizachyrium sanguineum (crimson bluestem),
Schizachyrium gracile (wire bluestem), Aster adnatus (scaleleaf aster),
and Acalypha chamaedrifolia (bastard copperleaf) (Bradley and Gann
1999, p. 12). B. mosieri may also be found in close association with
several other rare plants, including Chamaesyce deltoidea ssp.
deltoidea (deltoid spurge), Chamaesyce deltoidea ssp. adhaerens (wedge
sandmat), Chamaesyce deltoidea ssp. pinetorum (pineland sandmat),
Galactia smallii (Small's milkpea), Polygala smallii (tiny polygala),
and Argythamnia blodgettii (Blodgett's silverbush) (Bradley and Gann
199, p. 12).
Pine rockland occurs in a mosaic with primarily two other natural
community types--rockland hammock and marl prairie. Pine rockland
grades into rockland hammock; pine rockland has an open pine canopy,
and rockland hammock has a closed, hardwood canopy. Pine rockland is a
fire-maintained ecosystem--a well-maintained pine rockland is a
savanna-like forest, but, in the absence of fire, it will eventually
succeed into rockland hammock. Historically, fires often started in the
adjacent prairie wetlands and swept into the pinelands, which often
have suitable fuel conditions to support surface fires that consume
primarily leaf litter (pine needles and herbaceous fuel) and some
understory vegetation (Snyder et al. 1990, p. 258). Pine rockland
plants have adapted to frequent fires. Mature South Florida slash pine
is a highly fire-resistant variety, and even its seedlings have thicker
stems and are more fire-resistant than typical slash pine seedlings
(Snyder et al. 1990, p. 259). Aboveground portions of hardwood shrubs
are typically killed by fire, but often resprout below ground; palms
typically produce new growth post-fire from their unaffected apical
buds. Pine rockland herbs, including Brickellia mosieri, respond
favorably to fire with rapid regrowth and increased flowering. On one
private conservation area, B. mosieri has only been observed in flower
immediately after prescribed burning has occurred (Pine Ridge
Sanctuary; Glancy 2013, pers. comm.).
Fire is important for the removal of litter accumulation from the
limestone substrate and stimulation of herbaceous growth as well as for
maintaining an open shrub layer. Evaluation of herbaceous layers post-
fire suggests that pine rocklands may have evolved under a wide range
of fire frequency, and some degree of variation in burn season,
suggesting that pine rockland habitat historically existed as a mosaic
in the landscape. The natural fire regime of pine rockland is believed
to be approximately 3-7 years, or twice per decade, on average, with
fires primarily
[[Page 61277]]
occurring in the summer (wet season) in association with lightning
strikes. As time since fire increases, leaf litter deepens and the
shrub layer becomes denser, eventually shading out understory species
and preventing germination of new plants, which require exposed
substrate and high light conditions. If fire is excluded for 20-30
years, hardwoods will come to dominate the community and hammock
conditions will prevail, which further discourage fires from spreading
except in drought conditions.
Pine rocklands are also susceptible to natural disturbances such as
hurricanes and other severe storms, during which trees may be killed,
thereby helping to maintain the open canopy that is essential to pine
rockland plants such as Brickellia mosieri. This species was first
observed in flower on Pine Ridge Sanctuary after Hurricane Andrew made
landfall in south Florida in 1992 (Glancy 2013, pers. comm.). During
such events, pine rocklands near the coast may be temporarily inundated
by saltwater which can also kill or damage vegetation (Snyder et al.
1990, p. 251; URS Corporation Southern et al. 2007, p. 11). In
addition, though rare, freeze events can kill tropical plants in the
open understory, helping to reduce hardwood encroachment (Service 1999,
p. 3-167; FNAI 2010, p. 63). These sporadic, but potentially major,
disturbances along with burning, create the dynamic nature of the pine
rockland habitat, in which some currently unsuitable areas may become
open in the future, while areas currently open may develop more dense
canopy over time, eventually rendering that portion of the pineland
unsuitable for B. mosieri and other pine rockland endemic plants.
Pine rockland on the Miami Rock Ridge can also occur within lower,
seasonally flooded marl prairies, which differ from pine rockland in
having no pines, an understory dominated by grasses and sedges, and a
minimal cover of shrubs (FNAI 2010, p. 63). Where pine rockland occurs
close to the ocean, it may be bordered by mangrove swamp or salt marsh
and can receive flooding by extremely high tides (FNAI 2010, p. 63).
Pine rocklands on the northern Miami Rock Ridge grade into scrub and
sandhill vegetation where the three communities intermix in areas with
deep sands and rock outcrops (Snyder et al. 1990, p. 257).
Historical Range
Brickellia mosieri is endemic to the pine rocklands of the Miami
Rock Ridge in Miami-Dade County. It was historically known from central
and southern Miami-Dade County from South Miami to Florida City, a
range of approximately 36.2 km (22.5 mi), along the Miami Rock Ridge
(Bradley and Gann 1999, p. 11). However, Bradley and Gann (1999, p. 11)
state that herbarium specimens have not been studied from the New York
Botanical Garden, so the full extent of its historical range is
unknown. Available herbarium specimens and other records for this plant
(Bradley and Gann 1999, p. 16; Wunderlin and Hansen 2008, page numbers
not applicable) do not give precise or accurate location information.
Current Range, Population Estimates, and Status
Brickellia mosieri is currently distributed from central and
southern Miami-Dade County from SW 120 St. (latitude ca. 25'' 39.4) to
Florida City (latitude ca. 25'' 26.0), suggesting its historical range
has contracted at least 4.8 km (3 mi), or more than 13 percent (Bradley
and Gann 1999, p. 11). At least 9 known populations on private lands
have been extirpated including: Sunset Drive and 71 Court (site
developed; last observation in 1968); Palms Woodlawn Cemetery (site
developed; last observation in 1992); Turnpike Extension and 93rd
Terrace (site destroyed; confirmed extirpated in 2007); plus at least 6
of 18 undated occurrences reported by Alan Herndon (Bradley and Gann
1999, p. 12; Bradley 2007, pers. comm.). In addition, several of
Herndon's 18 sites experienced impacts to habitat through disturbance
or invasion by nonnative plants or dense hardwoods, and B. mosieri may
no longer occur at these sites (Bradley and Gann 1999, p. 12).
The number of extant occurrences of this species is somewhat
uncertain due to the lack of complete and recent survey information,
which is primarily a function of the number of populations that occur
on private lands, making them difficult to survey. In addition,
Brickellia mosieri can be extremely difficult to identify when not in
flower, making it difficult to confidently determine when a population
has been extirpated. The most complete survey that included the species
was the 2004-2005 mapping by IRC of natural forest communities (NFCs;
pinelands and hardwoods) in Miami-Dade County outside of ENP. IRC
mapped both public and private NFCs where the county government
obtained landowner permission or determined it was not necessary. This
survey found B. mosieri on six privately owned parcels, including on
the University of Miami Richmond campus (formerly the U.S. Naval
Observatory). Surveys of populations on public lands, specifically
those owned or managed by the County, occur more commonly and provide a
more detailed assessment of the species' status on selected preserves.
B. mosieri was not found during a 2-year project intended to survey and
map nonnative and rare plants along Florida Department of
Transportation (FDOT) rights-of-way within Miami-Dade County (Gordon et
al. 2007, pp. 1, 36).
Based on the best available data, we classified those occurrences
of Brickellia mosieri that have not been confirmed extirpated as either
extant (status confirmed within the last 10 years), possibly extant
(reliable data are greater than 10 years but less than 15 years old;
habitat is still extant), or unknown/historical (observation does not
include sufficient detail, or data are more than 15 years old; habitat
is still extant) (Table 1). Using this classification, populations of
B. mosieri are believed to occur on at least 17 (extant or presumed
extant) sites, and may possibly occur on up to another 5 (possibly
extant) sites, although most of these latter sites have been searched
in recent years without the species being found. B. mosieri may also
occur at three historical sites, although additional confirmation is
needed. Of the 17 extant occurrences, 9 occur on public conservation
lands, 4 occur on private lands managed for conservation, and 4 occur
on private lands with unknown management (Table 1). Four of the
populations on public conservation lands, including two of the three
large (>100 plants) monitored populations, occur adjacent to one
another in the Richmond Pineland Complex.
Bradley and Gann (1999, p. 12) estimated population size using a
logarithmic scale. On that scale, the total population of the species
in 1999 was estimated at 1,001-10,000 plants (with the exact number
probably between 5,000 and 7,000 plants), and was thought to be
declining (Bradley and Gann 1999, p. 12). Since that time, the estimate
for the largest population (Larry and Penny Thompson Park, 1,001-10,000
plants in 1999) has decreased to 101-1,000 plants, with adjacent areas
(University of Miami, Zoo Miami, Martinez Pineland) estimated to hold
another 112-1,100 plants combined (Possley 2013b, pers. comm.).
Additional plants are suspected to occur on adjacent privately owned
parcels in the Richmond Pineland Complex (Possley 2013a, pers. comm.).
The only other monitored population estimated to be composed of greater
than 100 plants occurs on the Navy Wells Pineland Preserve, located
approximately 20 km (12.5 mi) southwest at the southern end
[[Page 61278]]
of the species' current range. Another large population was observed on
a private parcel situated between Navy Wells and the Richmond
Pinelands; however this property has not been surveyed since 2004.
Smaller populations occur on pine rockland fragments spread across the
landscape, most no more than approximately 3.2 km (2 mi) from their
nearest neighboring population--the major exception to this is a 7.2-km
(4.5-mi) gap between the populations on Quail Roost Pineland and Camp
Owaissa Bauer. Based on the 17 populations considered to be extant, the
current total population estimate is between 515 and 4,935 plants,
although the actual number of individuals is probably closer to between
2,150 and 3,700 (Table 1). Based on current estimates, the total
population of B. mosieri has apparently declined by approximately 50
percent since 1999.
Table 1--Extant and Historical Populations of Brickellia mosieri--for
Those Populations Occurring Within a County-Designated Natural Forest
Community (NFC) Parcel, NFC Number Is Provided if Available. The NFC
Number Format Is a Letter Designating Primary Habitat Type Within the
NFC (``P'' for Pine Rockland, ``H'' for Hammock), Followed by a 1-3
Digit Number Assigned by the County
------------------------------------------------------------------------
Ownership (* Population range
Population (NFC if denotes lands (number of plants
applicable (P-)) managed for and year if
conservation) available)
------------------------------------------------------------------------
Extant: Regularly monitored populations--status confirmed within last 5
years.
------------------------------------------------------------------------
Navy Wells Pineland Preserve (P- State of Florida 101-1,000 (272 in
415). (Florida Keys 2009).\1\
Aqueduct
Authority) and
Miami-Dade
County*.
Pine Shore Pineland Preserve (P- Miami-Dade County* 11-100 (77-118 in
48). 2009).\1\
Quail Roost Pineland (P-144).... State of Florida-- 11-100 (23 in
managed by Miami- 2011).\1\
Dade County*.
Richmond Pinelands Complex-- Miami-Dade County* 101-1,000 (815 in
Larry and Penny Thompson Park 2008).\1\
(P-391).
Richmond Pinelands Complex--Zoo Miami-Dade County* 101-1,000 (742 in
Miami (P-391). 2009).\1\
Rockdale Pineland (P-52)........ State of Florida-- 1-10 (5 in
managed by Miami- 2010).\1\
Dade County*.
Ron Ehman Park.................. Miami-Dade School 11-100 (31-45 in
Board--managed by 2011).\1\
Miami-Dade
County*.
West Biscayne Pineland (P-295).. State of Florida-- 11-100 (15-150 in
managed by Miami- 2008).\1\
Dade County*.
------------------------------------------------------------------------
Presumed Extant: Populations not regularly monitored--status confirmed
within last 10 years.
------------------------------------------------------------------------
P-132........................... Private*.......... 1-10.\2\
P-295........................... Private........... 101-1,000.\2\
P-297........................... Private........... 11-100.\2\
P-316........................... Private*.......... 11-100.\2\
P-365........................... Private........... 11-100.\2\
Pine Ridge Sanctuary (P-310).... Private*.......... 11-100.\3\
Porter Russell Pineland Preserve Private--Tropical 10-15.\4\
(P-160). Audubon Society*.
Richmond Pinelands Complex -- Miami-Dade County* Unknown
Martinez Pineland (P-391). (previously
grouped with
Larry and Penny
Thompson Park).
Richmond Pinelands Complex -- Private--Universit 11-100.\2\
University of Miami, Richmond y of Miami.
Campus (P-391).
------------------------------------------------------------------------
Possibly Extant: Habitat extant but status last confirmed 10-15 years
ago.
------------------------------------------------------------------------
Camp Choee (P-397).............. Private--Girls 11-100.\5\
Scouts of
Tropical Florida.
Camp Owaissa Bauer (H-681)...... Miami-Dade County* 11-100.\5\
Panther Pineland (P-338)........ Private*.......... 11-100.\5\
Seminole Wayside Park (P-365)... Miami-Dade County* 11-100.\5\
Tamiami Pinelands Complex State of Florida-- 10-100.\5\
Addition (P-6.00). managed by Miami-
Dade County*.
------------------------------------------------------------------------
Unknown/Historical: Habitat extant but records regarding occurrence are
limited and/or 15 years old.
------------------------------------------------------------------------
Ingram Pineland (P-360)......... State of Florida-- Unknown.\6\
managed by Miami-
Dade County*.
Navy Wells 2 (P-329)... Miami-Dade School Unknown.\7\
Board.
Nixon Smiley Pineland Preserve Miami-Dade County* Unknown.\8\
(P-370).
------------------------------------------------------------------------
\1\ Possley 2013b, pers. comm.
\2\ Bradley and Gann 2005, page numbers not applicable.
\3\ Glancy 2013, pers. comm.
\4\ Bradley 2008a, pers. comm.
\5\ Bradley and Gann 1999, p. 15.
\6\ IRC 2005, page numbers not applicable.
\7\ FNAI 2011, page numbers not applicable.
\8\ IRC 1999, p. 2; IRC 2013, page numbers not applicable.
[[Page 61279]]
Demographic, Reproductive Biology, and Population Genetics
Little research has been done into the demography, reproductive
biology, or genetics of Brickellia mosieri. Field observations indicate
that the species does not usually occur in great abundance--populations
are typically sparse and contain a low density of plants even in well-
maintained pine rockland habitat (Bradley and Gann 1999, p. 12).
Reproduction is sexual (Bradley and Gann 1999, p. 12). While specific
pollinators or dispersers are unknown, flower morphology suggests this
species may be pollinated by butterflies, bees, or both (Koptur 2013,
pers. comm.); wind is one likely dispersal vector (Gann 2013b, pers.
comm.). Flowering takes place primarily in the fall (August-October),
but individuals may be found in flower during most of the year (Bradley
and Gann 1999, p. 12).
Linum carteri var. carteri
Description
Linum carteri var. carteri (Family: Linaceae) is an annual or
short-lived perennial herb endemic to Miami-Dade County, where it grows
in pine rocklands, particularly in disturbed pine rocklands (Bradley
and Gann 1999, p. 70). Its stem is erect, 23-36 cm (9.0-14.2 in) tall,
commonly branched near the base, and puberulent (covered with minute
hairs). Its leaves are slender (18-26 mm (0.7-1.0 in) long and 0.8-1.2
mm (0.03-0.05 in) wide), entire, alternate, and closely overlap at the
base of the plant. This variety has stipules (pair of appendages at the
base of the petiole, which is the stalk by which a leaf is attached to
a stem) with paired dark glands. Its inflorescence (cluster of flowers
arranged on a branching stem) is an ascending or spreading cyme
(usually flat-topped or convex flower cluster in which the main axis
and each branch end in a flower that opens before the flowers below or
to the side of it), with yellow petals that are broadly obovate (egg-
shaped), 9-17 mm (0.35-0.67 in) long, and quickly deciduous. The fruit
is straw-colored, ovoid, 4.1-4.6 mm (0.16-0.18 in) long, 3.4-3.7 mm
(0.13-0.15 in) in diameter, and dehisces (opens spontaneously at
defined places) into five two-seeded segments; seeds are narrowly
ovoid-elliptic, 2.3-2.8 mm (0.09-0.11 in) long, 1.0-1.3 mm (0.04-0.05
in) wide. In habit and flower, the plant closely resembles Piriqueta
caroliniana (Pitted stripeseed) in the Turneraceae (Bradley and Gann
1999, p. 70).
Taxonomy
According to Bradley and Gann (1999, p. 70), Linum carteri was
named by Small in 1905; in 1907, he put it in a segregate genus,
calling it Cathartolinum carteri. His concept of the taxon included
both pubescent and glabrous (smooth, without hairs) plants, with or
without stipular (having stipules) glands. In 1963, Rogers renamed the
plants as a variety of Linum rigidum, noting the close relationship of
Florida plants to those in the Western United States. In 1968, he split
the taxon into two varieties, calling pubescent plants Linum carteri
var. carteri, and segregating the glabrous plants as Linum carteri var.
smallii, basing the division on new genetic data from Mosquin and
Hayley (1967, pp. 1278-1283) and his own morphological data (Bradley
and Gann 1999, p. 70). L. c. var. carteri was treated as endemic to
Miami-Dade County, while L. c. var. smallii was slightly more
widespread in southern Florida (Bradley and Gann 1999, p. 70). Long and
Lakela (1971), Robertson (1971), and Wunderlin (1998) have used this
same taxonomy (Bradley and Gann 1999, p. 70). ITIS (2013, page numbers
not applicable) uses the name Linum carteri var. carteri and indicates
that this species' taxonomic standing is accepted. Based upon the best
available scientific information, Linum carteri var. carteri is a
distinct taxon, endemic to Miami-Dade County in Florida. Synonyms
include Cathartolinum carteri and Linum rigidum var. carteri (ITIS
2013b, page numbers not applicable).
Climate
The climate of south Florida where Linum carteri var. carteri
occurs is described above for Brickellia mosieri.
Habitat
Like Brickellia mosieri, Linum carteri var. carteri grows
exclusively on the Miami Rock Ridge in Miami-Dade County outside the
boundaries of ENP. Its known populations are found at elevations
ranging from approximately 1.6-4.8 m (5.2-15.9 ft), with occurrences
distributed fairly regularly throughout this range. Herbarium label
data indicated that L. c. var. carteri once occurred in pine rocklands
with sand or marl deposits (Bradley and Gann 1999, p. 75). In addition,
one specimen was taken from Brickell Hammock, but it is more likely
that the plant was collected outside of the hammock or along the
roadside (Bradley and Gann 1999, p. 75). Currently, this variety is
associated with pine rocklands that have undergone some sort of
substrate disturbance (e.g., firebreaks, canal banks, edges of railway
beds). All known occurrences are within either scarified pine rockland,
disturbed areas adjacent to or within pine rocklands, or in completely
disturbed areas having a limestone substrate (Bradley and Gann 1999, p.
71; Bradley 2013, pers. comm.). None of the known occurrences over the
last 15 years have been from a completely undisturbed pine rockland. L.
c. var. carteri responds positively to low competition and high light
conditions, and responds negatively to shading or litter accumulation.
Thus, it may have been excluded from much of its former habitat by
inadequate fire management (Bradley and Gann 1999, p. 71).
Alternatively, this variety may only proliferate on sites where exposed
substrate occurs following disturbance; historically this may have
occurred following hurricanes (e.g., under tip-up mounds), animal
disturbance, or fire (Gann 2013a, pers. comm.). More information is
needed to understand how this variety behaved in intact habitat before
modern human disturbance (Gann 2013a, pers. comm.).
The pine rockland community is described above for Brickellia
mosieri. The scarified pine rocklands and disturbed areas where Linum
carteri var. carteri occurs often supports a subset of the pine
rockland flora, as well as a component of weedy native and nonnative
plants, including Bidens alba var. radiata (beggarticks), Eremochloa
ophiuroides (centipede grass), Desmodium spp. (ticktrefoil), and
Stenotaphrum secundatum (St. Augustine grass) (Bradley and Gann 1999,
p. 71). L. c. var. carteri may grow in association with several other
rare species including Linum arenicola (sand flax), Dalea
carthagenensis var. floridana (Florida prairie-clover), and Argythamnia
blodgettii (Blodgett's silverbush) (Bradley and Gann 1999, p. 71).
The natural disturbance regime for pine rocklands is discussed
above for Brickellia mosieri and also applies to Linum carteri var.
carteri. Fellows et al. (2004, p. 95) suggested that fire could be
beneficial as it creates openings in the habitat, but that the
potential for adults to survive from rootstock is unknown (although
population recovery may be supported by the seed bank). Because areas
where the variety now exists support native pine rockland herbaceous
and grass plant species, periodic mowing of these areas may partially
replace the role of fire in maintaining an open understory.
[[Page 61280]]
Historical Range
Linum carteri var. carteri was first collected in 1903 between the
Coconut Grove and Cutler areas of Miami, and since that time, it has
been found in pine rocklands from as far north as the Brickell Hammock
area to as far south as the Naranja area (Gann et al. 2002, p. 463).
Bradley and Gann (1999, p. 70) indicated that it has been found at many
widespread locations, from Coconut Grove (latitude 25[deg] 43.8') to
southern Miami-Dade County, terminating near SW 280 Street (latitude
25[deg] 30.4'), a range of about 39 km (24 mi). However, they believe
that several of these occurrences represented misidentifications, and
that the plants actually were either Linum arenicola (sand flax) or
Linum carteri var. smallii (Bradley and Gann 1999, p. 72). For example,
a previous report of the plant occurring at Homestead Air Reserve Base
site is now considered to be erroneous (Bradley 2008b, pers. comm.).
Austin et al. (1980, page number not applicable) noted that there were
four historical sites for this variety in a study of southern Florida,
although only one site remained in 1980; they attributed the 75 percent
decline to urbanization.
Current Range, Population Estimates, and Status
Linum carteri var. carteri is currently found from R. Hardy
Matheson Preserve (near Pinecrest) southwest to Naranja/Modello, with a
distance of approximately 27.3 km (17 mi) between the farthest
locations. The apparent reduction in its historical range (11.2 km (7.2
mi), or 30 percent) has occurred entirely in the northern portion,
between Pinecrest and Coconut Grove, primarily due to urban
development. Similarly, much of the habitat within the variety's
current range has been destroyed (Gann et al. 2002, p. 463). At least
five known populations have been extirpated including: Brickell Hammock
(site developed; last observation in 1911); Red Road/114 Terrace (site
developed; last observation in 1969); Deering Estate at Cutler (not
sighted since 1980s; unknown reason); Ponce and Riviera Pineland (site
developed in 2004); and Cocoplum Development (site developed in 2005)
(Bradley 2007, pers. comm.; Bradley and van der Heiden 2013, pp. 14-
16). Bradley and Gann (1999, p. 71) described nine known populations
(only three of these occurring on conservation lands) with an estimated
total population of 100-1,000 individuals; its status was thought to be
possibly declining. Fellows et al. (2001, p. 2) estimated the total
population to be 9,540-10,300 plants across six populations in 2001,
with one population sustaining the vast majority (Chapman Field, U.S.
Department of Agriculture (USDA) Subtropical Horticultural Research
Station; 7,500 individuals). L. c. var. carteri was not found during a
2-year project intended to survey and map nonnative and rare plants
along FDOT rights-of-way within Miami-Dade County (Gordon et al. 2007,
pp. 1, 36).
In 2012, IRC (Bradley and van der Heiden 2013, entire) conducted a
status survey for Linum carteri var. carteri to include extant
occurrences, historical locations, and new survey stations. Because
they had previously conducted a comprehensive survey of all pine
rockland habitat in 2004-2005 (during which, L. c. var. carteri was not
found on any new sites), this habitat was excluded from new surveys.
Canals within urban Miami-Dade County that intersected with the pine
rockland soils of the Miami Rock Ridge were surveyed, as were
additional disturbed sites with remnant native vegetation in close
proximity to existing sites. L. c. var. carteri was found at seven
locations containing approximately 1,313 individuals; populations
ranged in size from a single plant to 700 plants, with a median of 18
plants (Table 2; Bradley and van der Heiden 2013, p. 6). One occurrence
(at Gifford Arboretum Pineland), which had not been observed since the
1990s but whose habitat was still extant, was deemed ``Historical'' and
may reappear there (Bradley and van der Heiden 2013, p. 14). Of the
seven extant occurrences, five populations are on publicly owned lands,
but only three of these are managed for the conservation of natural
resources (Table 2). Four of the populations occur near the north end
of the variety's range (near R. Hardy Matheson Preserve), and three
occur near the south end (near Camp Owaissa Bauer), with an
approximately 16-km (10-mi) gap between the closest populations of
these groups. Within each grouping, populations are approximately 1.3-
4.3 km (0.8-2.7 mi) apart.
Because this variety is known to be a short-lived perennial with
widely fluctuating numbers of individuals (Maschinski et al. 2003, p.
v; 2004, p. iv), as well as being difficult to find when not in flower,
we include an estimate of population range using the logarithmic scale
(Table 2) to account for these characteristics and to provide a
comparison to the previous total population estimates. Using the
logarithmic scale, the total population estimate is 337-3,310 plants.
However, it should be noted that most 2012 observations were at the low
end of the corresponding logarithmic range such that the resulting high
end for the total population estimate may be a gross overestimate of
the actual population. Based strictly on 2012 observations, the total
population estimate may be closer to 1,300 individuals. Comparing these
estimates to the 1999 and 2003 population estimates generally supports
the boom-and-bust nature of Linum carteri var. carteri, although the
significant decline since 2001 could also potentially indicate a
declining trend in one or more populations (especially USDA Chapman
Field and R. Hardy Matheson Preserve).
Table 2--Extant and Historical Populations of Linum carteri var.
carteri--for Those Populations Occurring Within a County-Designated
Natural Forest Community (NFC) Parcel, NFC Number is Provided if
Available. The NFC Number Format is a Letter Designating Primary Habitat
Type Within the NFC (``P'' for Pine Rockland, ``H'' for Hammock),
Followed by a 1-3 Digit Number Assigned by the County
------------------------------------------------------------------------
Ownership (*
Population (NFC if denotes lands Population range (est.
applicable (P-)) managed for number of plants in
conservation) 2012) \1\
------------------------------------------------------------------------
Extant: Population status confirmed in 2012 surveys conducted by IRC.
------------------------------------------------------------------------
C-103 Canal................. State of 1-10 (1).
Florida--South
Florida Water
Management
District.
Camp Owaissa Bauer Addition State of 11-100 (13).
(P-255.4). Florida--manag
ed by Miami-
Dade County*.
Chapman Field, USDA Federal--U.S. 101-1,000 (700).
Subtropical Horticultural Department of
Research Station (portions Agriculture.
are P-63).
Montgomery Botanical Center. Private--Montgo 11-100 (12).
mery Botanical
Center.
Old Dixie Pineland.......... Private........ 11-100 (18).
[[Page 61281]]
R. Hardy Matheson Preserve State of 101-1,000 (374).
(H-634). Florida--manag
ed by Miami-
Dade County *.
Rockdale Pineland Addition Miami-Dade 101-1,000 (195).
(P-52). County *.
------------------------------------------------------------------------
Historical: Population not observed for 10 years, but habitat
extant.
------------------------------------------------------------------------
Gifford Arboretum Pineland.. Private........ 0.
------------------------------------------------------------------------
\1\ Source for number of plants is Bradley and van der Heiden (2013, pp.
12-16).
Demographics, Reproductive Biology and Population Genetics
The reproductive ecology and biology of Linum carteri var. carteri
is not well understood, but reproduction is sexual (Bradley and Gann
1999, p. 71). L. c. var. carteri is capable of flowering throughout the
year, but tends to have most abundant flowering and fruiting following
rain (Maschinski and Walters 2008, p. 28). Tatje (1980, p. 2) indicated
that the variety requires disturbance to bloom, although this theory
was not supported by observations of Maschinski et al. (2003, pp. 37-
39). While specific pollinators are unknown, flower morphology suggests
this variety may be pollinated by butterflies, bees, or both (Koptur
2013, pers. comm.). Alternatively, Mosquin and Hayley (1967, p. 1278)
suggested L. c. var. carteri may be self-pollinated. Dispersers are
also unknown, although historically water may have played a role in
dispersal when summer high-water conditions in adjacent wet prairies
may have inundated portions of pine rocklands (Gann 2013b, pers.
comm.). The maximum magnitude and frequency of seed production is
unknown, although Maschinski and Walters (2007, p. 56) indicate plants
can produce up to 62 fruits. Some fruits dehisce in a characteristic 5-
parted star pattern, while others never dehisce (Fellows 2002, Appendix
D2 p. 1).
Preliminary demographic monitoring of Linum carteri var. carteri
showed that, for adult reproductive plants, average plant growth was
fairly constant from July through October, flowering and fruit
production were most abundant in July, and plant mortality increased
during the fall months (Maschinski et al. 2002, p. iv). Maschinski and
Walters (2008, p. 27) studied in situ germination and growth-to-
maturity of plants growing in the wild at two sites (mown and
undisturbed) from January 2006 until July 2007. Field germination
varied across sites and season of seed production, with seed produced
in winter (January) having low to no germination and longer germination
times than seeds produced in summer (July). Of the 51 seeds that
germinated across all trials, they followed the growth of 32
seedlings--of these, only 6 set fruit (Maschinski and Walters 2008, p.
27). The mean time to set first bud was 197 2.4 days,
while mean time to first fruit set was 226 2.3 days
(Maschinski and Walters 2008, p. 27). The 226-day growth-to-maturity
enables this variety to contribute seeds to a next generation in a
relatively short period (Maschinski and Walters 2008, p. 28). Once
mature, individuals may live one to several years producing multiple
fruits (Maschinski and Walters 2008, p. 28). Growth-to-maturity may be
influenced by season of germination, with summer-germinating seeds
possibly reaching maturity more rapidly than seedlings that germinate
in the fall or winter (Maschinski and Walters 2008, p. 28). Similarly,
seeds produced during different seasons may differ in their germination
rates, dormancy breaking requirements, and rates of growth (Maschinski
and Walters 2008, p. 28).
To examine population viability in response to disturbance, long-
term demographic studies were conducted from June 2003 through July
2007 at a disturbed (mown) site and an undisturbed site; in May 2006, a
site having both disturbed and undisturbed sections was added
(Maschinski 2006, p. 82; Maschinski and Walters 2007, p. 55). Results
were mixed with regard to demographic responses between sites.
Maschinski (2006, p. 83) reported that Linum carteri var. carteri has
typical behavior for an early successional plant. Significantly higher
densities of plants were found at the mown sites where competition with
other plants is decreased, although changes in number of plants between
sites and treatments were variable (Maschinski and Walters 2007, p.
56). Germination varied across sites and season of seed production as
discussed above, although there was greater germination on the
undisturbed site in both seasons. Fruiting was also variable across
years and sites; while there was no clear effect of mowing, plants
growing on mown sites were shorter, which may affect fruiting
magnitude. While mowing does not usually kill adult plants, if mowing
occurs prior to plants reaching reproductive status, it can also delay
reproduction (Maschinski and Walters 2007 pp. 56-57). If such mowing
occurs repeatedly, reproduction of those plants would be entirely
eliminated. If, instead, mowing occurs at least three weeks after
flowering, there would be a higher probability of adults setting fruit
prior to mowing; mowing may then act as a positive disturbance by both
scattering seeds and reducing competition (Maschinski and Walters 2007,
p. 57). The exact impacts of mowing thus depend on the timing of the
mowing event, rainfall prior to and following mowing, and the numbers
of plants in the population that have reached a reproductive state.
Although population viability models projected declines in mown
sites, and fairly stable population growth in undisturbed sites, high
variation in the models suggest caution be used in interpreting
results. One likely factor in the high year-to-year variation observed
is variation in weather, which was most apparent in the model for
undisturbed habitat. Preliminary models indicated that population
viability was greatly affected by reproductive rates and whether there
is a persistent seed bank (Maschinski 2006, p. 83; Maschinski and
Walters 2007, p. 56). Models indicate that the transition from seedling
to adult and adult reproduction greatly influence population
trajectories (Maschinski and Walters 2007, p. 56). However, more
frequent monitoring (with frequency partially dependent of
[[Page 61282]]
mowing regime) is needed to determine threshold reproductive values for
population growth and whether disturbance regime has a persistent
impact on population demographics (Maschinski 2013, pers. comm.).
Summary of Factors Affecting the Species
Section 4 of the Act (16 U.S.C. 1533), and its implementing
regulations at 50 CFR part 424, set forth the procedures for adding
species to the Federal Lists of Endangered and Threatened Wildlife and
Plants. Under section 4(a)(1) of the Act, we may determine a species to
be endangered or threatened due to one or more of the following five
factors: (A) The present or threatened destruction, modification, or
curtailment of its habitat or range; (B) overutilization for
commercial, recreational, scientific, or educational purposes; (C)
disease or predation; (D) the inadequacy of existing regulatory
mechanisms; or (E) other natural or manmade factors affecting its
continued existence. Listing actions may be warranted based on any of
the above threat factors, singly or in combination. Each of these
factors as applied to these two plants is discussed below.
A. The Present or Threatened Destruction, Modification, or Curtailment
of Its Habitat or Range
Brickellia mosieri and Linum carteri var. carteri have experienced
substantial destruction, modification, and curtailment of their habitat
and range (see Status Assessment, above). Specific threats to these
plants included in this factor include habitat loss, fragmentation, and
modification caused by development (i.e., conversion to both urban and
agricultural land uses) and inadequate fire management. Each of these
threats and its specific effects on these plants are discussed in
detail below.
Human Population Growth and Development
The pine rockland community of south Florida, to which both plants
are endemic, is critically imperiled globally (FNAI 2012, p. 27). Since
the 1800s, residential and commercial development and agriculture have
drastically reduced the habitat for these plants throughout pine
rocklands in south Florida. When the Florida East Coast (FEC) Railroad
reached Miami in 1896, industrial logging began and pinelands were
clearcut over the next 50 years (Snyder et al. 1990, p. 271). Groves of
tropical trees were planted on well-drained (and previously cleared)
pinelands; with the invention of the ``rock plow'' in 1954, large-scale
clearing of pinelands for row crops began (Snyder et al. 1990, p. 272).
Due to these impacts combined with increased residential development
from the early 1900s, pine rockland habitat in Miami-Dade County,
including ENP, was reduced to about 11 percent of its natural extent,
from approximately 74,000 hectares (ha) (183,000 acres (ac)) to only
8,140 ha (20,100 ac) in 1996 (Kernan and Bradley 1996, p. 2). Outside
of ENP, only about 1 percent of the Miami Rock Ridge pinelands have
escaped clearing, and much of what is left is in small remnant blocks
isolated from other natural areas (Herndon 1998, p. 1). Habitat loss
continues to occur in these plants' ranges, and most remaining suitable
habitat has been negatively altered by human activity.
While Miami-Dade County has developed a network of public
conservation lands including some of these pine rocklands, much of the
remaining habitat occurs on private lands as well as publically owned
lands not managed for conservation. Species occurrences and suitable
habitat remaining on these lands are threatened by habitat loss and
degradation, and threats are expected to accelerate with increased
development. The human population within Miami-Dade County, which
comprises the historical and current ranges for these plants and,
therefore, supports all of the remaining occurrences, is currently
greater than 2.4 million people, and the population is expected to grow
to more than 4 million by 2060, an annual increase of roughly 30,000
people (Zwick and Carr 2006, p. 20). Approximately 47 percent (8 sites)
of extant Brickellia mosieri occurrences, and 28 percent (2 sites) of
extant Linum carteri var. carteri occurrences, are located on private
land within this County; however, it is likely that these plants will
be lost from most of these sites, with increased development pressure.
Development, such as road construction, can also threaten these
plants' habitat on public lands. This is especially true for Linum
carteri var. carteri, whose association with disturbed areas is more
likely to result in occurrences in firebreaks and other edge areas
subject to increased development pressure and effects. For example, one
colony of 11-100 L. c. var. carteri individuals located within the FEC
Railway right-of-way at Old Dixie Pineland was destroyed by the
construction of the South Miami-Dade Busway in 2007 (Bradley and van
der Heiden 2013, p. 15). In addition, one of the two colonies of L. c.
var. carteri on Camp Owaissa Bauer Addition occurs along the edge of
pine rockland along Krome Avenue, and is threatened by the proposed
widening of that road.
Another human-related factor that can modify public and private
lands alike is the potential for high levels of nutrients from
agricultural and urban areas to enter into pine rockland systems. Such
chemical alteration of pine rockland soil, which has naturally low
amounts of phosphorus and nitrogen, can result in changes to vegetation
composition and structure, at the expense of pine rockland endemics
such as Brickellia mosieri and Linum carteri var. carteri. This is
currently not considered a problem in most intact pine rockland
systems, but could likely be an issue where restoration is required
(Gann 2013a, pers. comm.).
Habitat Fragmentation
Habitat fragmentation reduces the size of plant populations, and
increases spatial isolation of remnants. Barrios et al. (2011, p. 1062)
investigated the effects of fragmentation on a threatened pine rockland
plant, Angadenia berteroi (pineland golden trumpet), and found that
abundance and fragment size were positively related. Possley et al.
(2008, p. 385) studied the effects of fragment size on species
composition in south Florida pine rocklands, and found that plant
species richness and fragment size were positively correlated (although
some small fragments supported nearly as many species as the largest
fragment). Composition of fragmented habitat typically differs from
that of intact forests, as isolation and edge effects increase leading
to increased abundance of disturbance-adapted species (weedy species,
nonnative invasive species) and lower rates of pollination and
propagule dispersal (Laurence and Bierregaard 1997, pp. 347-350.; Noss
and Csuti 1997, pp. 284-299). The degree to which fragmentation
threatens the dispersal abilities of Brickellia mosieri and Linum
carteri var. carteri is unknown. Because B. mosieri is thought to be
dispersed, to some degree, by wind, dispersal-related impacts are
probably less than those experienced by L. c. var. carteri, which has
heavier seeds. In the historical landscape, where pine rockland
occurred within a mosaic of wetlands, water may have acted as a
dispersal vector for all pine rockland seeds, and especially for plants
such as L. c. var. carteri. In the current, fragmented landscape, this
type of dispersal would no longer be possible. While additional
dispersal vectors for L. c. var. carteri may include animals and (in
certain locations) mowing equipment, it is likely that
[[Page 61283]]
fragmentation has effectively reduced this taxon's ability to disperse.
While pollination research has not been conducted for Brickellia
mosieri or Linum carteri var. carteri, research regarding other species
and ecosystems provides valuable information regarding potential
effects of fragmentation to these plants. Effects of fragmentation on
pollinators may include changes to the pollinator community as a result
of limitation of pollinator-required resources (e.g., reduced
availability of rendezvous plants, nesting and roosting sites, and
nectar/pollen); these changes may include changes to pollinator
community composition, species abundance and diversity, and pollinator
behavior (Rathcke and Jules 1993, pp. 273-275; Kremen and Ricketts
2000, p. 1227; Harris and Johnson 2004, pp. 30-33). As a result, plants
in fragmented habitats may experience lower visitation rates, which in
turn may result in reduced seed production of the pollinated plant
(which may lead to reduced seedling recruitment), reduced pollen
dispersal, increased inbreeding, reduced genetic variability, and
ultimately reduced population viability (Rathcke and Jules 1993, p.
275; Goverde et al. 2002, pp. 297-298; Harris and Johnson 2004, pp. 33-
34).
In addition to effects on pollination, fragmentation of natural
habitats often alters other ecosystems' functions and disturbance
regimes. Fragmentation results in an increased proportion of ``edge''
habitat, which in turn has a variety of effects, including changes in
microclimate and community structure at various distances from the edge
(Margules and Pressey 2000, p. 248), altered spatial distribution of
fire (greater fire frequency in areas nearer the edge) (Cochrane 2001,
pp. 1518-1519), and increased pressure from nonnative invasive plants
and animals that may out-compete or disturb native plant populations.
The effects of fragmentation on fire go beyond edge effects and include
reduced likelihood and extent of fires, and altered behavior and
characteristics (e.g., intensity) of those fires that do occur. Habitat
fragmentation encourages the suppression of naturally occurring fires,
and has prevented fire from moving across the landscape in a natural
way, resulting in an increased amount of habitat suffering from these
negative impacts. High fragmentation of small habitat patches within an
urban matrix discourages the use of prescribed fire as well due to
logistical difficulties (see Fire Management, below). Forest fragments
in urban settings are also subject to increased likelihood of certain
types of human-related disturbance, such as the dumping of trash
(Chavez and Tynon 2000, p. 405). The many effects of habitat
fragmentation may work in concert to threaten the local persistence of
a species; when a species' range of occurrence is limited, threats to
local persistence increase extinction risk.
Fire Management
One of the primary threats to both of these plants is habitat
modification and degradation through inadequate fire management, which
includes both the lack of prescribed fire and suppression of natural
fires. Where the term ``fire-suppressed'' is used below, it describes
degraded pine rockland conditions resulting from a lack of adequate
fire (natural or prescribed) in the landscape. Historically, frequent
(approximately twice per decade), lightning-induced fires were a vital
component in maintaining native vegetation and ecosystem functioning
within south Florida pine rocklands (see Status Assessment, above). A
period of just 10 years without fire may result in a marked decrease in
the number of herbaceous species due to the effects of shading and
litter accumulation (FNAI 2010, p. 63). Exclusion of fire for
approximately 25 years will likely result in gradual hammock
development over that time period, leaving a system that is very fire
resistant if additional pre-fire management (e.g., mechanical hardwood
removal) is not undertaken.
Now, natural fires are unlikely to occur or are likely to be
suppressed in the remaining, highly fragmented pine rockland habitat.
The suppression of natural fires has reduced the size of the areas that
burn, and habitat fragmentation has prevented fire from moving across
the landscape in a natural way. Without fire, successional climax from
pine rockland to rockland hammock is rapid, and displacement of native
species by invasive nonnative plants often occurs. Understory plants
such as Brickellia mosieri and Linum carteri var. carteri are shaded
out by hardwoods and nonnatives alike. Shading may also be caused by a
fire-suppressed (and, in some cases, planted) pine canopy that has
evaded the natural thinning effects that fire has on seedlings and
smaller trees. Gann (2013a, pers. comm.) indicates this is also a
threat to pine rockland habitat on the Miami Rock Ridge. Whether the
dense canopy is composed of pine, hardwoods, nonnatives, or a
combination, seed germination and establishment are inhibited in fire-
suppressed habitat due to accumulated leaf litter, which also changes
soil moisture and nutrient availability (Hiers et al. 2007, pp. 811-
812). This alteration to microhabitat can also inhibit seedling
establishment as well as negatively influence flower and fruit
production (Wendelberger and Maschinski 2009, pp. 849-851), thereby
reducing sexual reproduction in fire-adapted species such as B. mosieri
and L. c. var. carteri (Geiger 2002, pp. 78-79, 81-83).
After an extended period of inadequate fire management in pine
rocklands, it becomes necessary to control invading native hardwoods
mechanically, since excess growth of native hardwoods would result in a
hot fire, which can be destructive. Mechanical treatments cannot
entirely replace fire because pine trees, understory shrubs, grasses,
and herbs all contribute to an ever-increasing layer of leaf litter,
covering herbs and preventing germination, as discussed above. Leaf
litter will continue to accumulate even if hardwoods are removed
mechanically. In addition, the ashes left by fires provide important
post-fire nutrient cycling, which is not provided via mechanical
removal.
Brickellia mosieri--All occurrences of Brickellia mosieri are
affected by some degree of inadequate fire management, with the primary
threat being shading by hardwoods (Bradley and Gann 1999, p. 15;
Bradley and Gann 2005, page numbers not applicable). While management
of some County conservation lands (e.g., those in Richmond Pinelands
complex and Navy Wells Pineland Preserve) includes regular burning,
other such lands can be severely fire-suppressed. For example, the B.
mosieri population at Pine Shore Pineland Preserve may be the most
endangered (due to lack of adequate fire management), and is expected
to be extirpated within 10 years if fires are not reintroduced (Possley
2013a, pers. comm.). Even in areas under active management, some
portions are typically fire-suppressed, thereby threatening populations
of this species.
Linum carteri var. carteri--Of the seven extant occurrences of
Linum carteri var. carteri, six are threatened to some degree by
inadequate fire management. Three of these populations (Camp Owaissa
Bauer Addition, Montgomery Botanical Center, and Rockdale Pineland)
occur adjacent to fire-suppressed pine rocklands (Bradley and van der
Heiden 2013, pp. 13-16). One population (R. Hardy Matheson Preserve)
occurs in previously cleared pine rockland habitat in areas of open
canopy gaps and exposed bare rock substrate (Bradley and van der Heiden
2013, p. 16). Pine rocklands at Chapman Field, USDA Subtropical
Horticultural Research Station are severely fire-
[[Page 61284]]
suppressed, and the plant now occurs only adjacent to the pine
rocklands or in nearby open fields (Bradley and van der Heiden 2013, p.
13). In addition, one historical population (at Gifford Arboretum
Pineland) may have been extirpated due to the effects of inadequate
fire management (Bradley and van der Heiden 2013, p. 14). Bradley and
Gann (1999, pp. 71-72) suggested that the lack of fires in most forest
fragments in Miami-Dade County during the last century may be one of
the reasons why this taxon occurs primarily in disturbed areas.
Implementation of a prescribed fire program in Miami-Dade County
has been hampered by a shortage of resources, and by logistical
difficulties and public concern related to burning next to residential
areas. Many homes have been built in a mosaic of pine rockland, so the
use of prescribed fire in many places has become complicated because of
potential danger to structures and smoke generated from the burns.
Nonprofit organizations such as IRC have similar difficulties in
conducting prescribed burns due to difficulties with permitting and
obtaining the necessary permissions as well as hazard insurance
limitations (Gann 2013a, pers. comm.). Few private landowners have the
means and/or desire to implement prescribed fire on their property, and
doing so in a fragmented urban environment is logistically difficult
and may be costly. One of the few privately owned pine rocklands that
is successfully managed with prescribed burning is Pine Ridge
Sanctuary, located in a more agricultural (less urban) matrix in the
southwestern portion of Brickellia mosieri's current range, which was
last burned in November 2010 (Glancy 2013, pers. comm.).
Conservation Efforts To Reduce the Present or Threatened Destruction,
Modification, or Curtailment of Habitat or Range
In 1979, Miami-Dade County enacted the Environmentally Endangered
Lands (EEL) Covenant Program, which reduces taxes for private
landowners of natural forest communities (NFCs; pine rocklands and
tropical hardwood hammocks) who agree not to develop their property and
manage it for a period of 10 years, with the option to renew for
additional 10-year periods (Service 1999, p. 3-177). Although these
temporary conservation easements provide valuable protection for their
duration, they are not considered under Factor D, below, because they
are voluntary agreements and not regulatory in nature. Miami-Dade
County currently has approximately 59 pine rockland properties enrolled
in this program, preserving 69.4 ha (172 ac) of pine rockland habitat
(Johnson 2012, pers. comm.). The vast majority of these properties are
small--only three are larger than 2 ha (5 ac)--and many are in need of
habitat management such as prescribed fire and removal of nonnative
invasive plants. Of the 59 pine rockland properties, three have known
populations of Brickellia mosieri. Two of these, a 1.3-ha (3.3-ac)
parcel and a 5.7-ha (14-ac) parcel, are in good overall condition. The
other, a 5.75-ha (14.2-ac) parcel, has heavy cover by exotics, and
illegal clearing of NFC vegetation was observed during a 2013 site
inspection. Thus, while EEL covenant lands have the potential to
provide valuable habitat for these plants and reduce threats in the
near term, the actual effect of these conservation lands is largely
determined by whether individual land owners follow prescribed EEL
management plans and NFC regulations (see Local under Factor D).
Since 2005, the Service has funded IRC to facilitate restoration
and management of privately owned pine rockland habitats in Miami-Dade
County. These programs included prescribed burns, nonnative plant
control, light debris removal, hardwood management, reintroduction of
pines where needed, and development of management plans. One of these
programs, called the Pine Rockland Initiative, includes 10-year
cooperative agreements between participating landowners and the
Service/IRC to ensure restored areas will be managed appropriately
during that time. Although most of these objectives have been achieved,
IRC has not been able to conduct the desired prescribed burns, due to
logistical difficulties as discussed above (see Fire Management).
Fairchild Tropical Botanic Garden (FTBG), with the support of
various Federal, State, local, and nonprofit organizations, has
established the ``Connect to Protect Network.'' The objective of this
program is to encourage widespread participation of citizens to create
corridors of healthy pine rocklands by planting stepping stone gardens
and rights-of-way with native pine rockland species, and restoring
isolated pine rockland fragments. By doing this, FTBG hopes to increase
the probability that pollination and seed dispersal vectors can find
and transport seeds and pollen across developed areas that separate
pine rockland fragments to improve gene flow between fragmented plant
populations and increase the likelihood that these plants will persist
over the long term. Although these projects may serve as valuable
components toward the conservation of pine rockland species and
habitat, they are dependent on continual funding, as well as
participation from private landowners, both of which may vary through
time.
B. Overutilization for Commercial, Recreational, Scientific, or
Educational Purposes
We have no evidence suggesting that overutilization for commercial,
recreational, scientific, or educational purposes is a threat to
Brickellia mosieri. Except for its rarity, the species does not possess
any attributes that would make it desirable to collectors, such as
showy foliage or flowers, and there are no known medicinal, culinary,
or religious uses for this species. We also have no evidence that
overutilization is a threat for Linum carteri var. carteri. However,
FTBG states that the species is a member of the Linum rigidum complex
and, therefore, may contain the [alpha]-carotenoids leutin and 5,6-
monoepoxide (Robertson 1971, p. 658), both of which are hypothesized to
reduce the risk of certain cancers (Fellows et al. 2004, p. 96). At
this time, we have no evidence indicating that L. c. var. carteri is
being used for this purpose. Therefore, we believe that collection for
medicinal purposes is not a threat at this time. Based on our analysis
of the best available scientific and commercial information, we find
that collecting for commercial or scientific reasons or recreational
activities is not a threat to B. mosieri or L. c. var. carteri in any
portion of their ranges at this time and is not likely to become so in
the future. Threats to these plants related to other aspects of
recreation and similar human activities (i.e., not related to
overutilization) are discussed in Factor E.
C. Disease or Predation
No diseases or incidences of predation have been reported for
Brickellia mosieri and Linum carteri var. carteri.
D. The Inadequacy of Existing Regulatory Mechanisms
Under this factor, we examine whether existing regulatory
mechanisms are inadequate to address the threats to the species
discussed under the other factors. Section 4(b)(1)(A) of the Act
requires the Service to take into account ``those efforts, if any,
being made by any State or foreign nation, or any political subdivision
of a State or foreign nation, to protect such species. . . .'' In
relation to Factor D, we interpret this language to require the Service
to consider
[[Page 61285]]
relevant Federal, State, and tribal laws, plans, regulations, and other
such mechanisms that may minimize any of the threats we describe in
threat analyses under the other four factors, or otherwise enhance
conservation of the species. We give strongest weight to statutes and
their implementing regulations and to management direction that stems
from those laws and regulations. An example would be State governmental
actions enforced under a State statute or constitution, or Federal
action under statute.
Federal
These plants have no Federal regulatory protection in their known
occupied and suitable habitat. Neither taxon occurs on National
Wildlife Refuge or National Park land. Brickellia mosieri is known to
occur on Federal lands within the Richmond Pinelands Complex, including
lands owned by the U.S. Coast Guard and the National Oceanic and
Atmospheric Association (NOAA; small portion of Martinez Pineland). The
only known Federal occurrence of Linum carteri var. carteri is on
Chapman Field USDA Subtropical Horticultural Research Station. There
are no Federal protections for candidate species on these properties.
These plants primarily occur on State- or County-owned and private land
(Tables 1 and 2), and development of these areas will likely require no
Federal permit or other authorization. Therefore, projects that affect
them are usually not analyzed under the National Environmental Policy
Act (NEPA) (42 U.S.C. 4321 et seq.).
State
Brickellia mosieri and Linum carteri var. carteri are listed on the
Regulated Plant Index as endangered under Chapter 5B-40, Florida
Administrative Code. The Regulated Plant Index also includes all
federally listed endangered and threatened plant species. This listing
provides little or no habitat protection beyond the State's Development
of Regional Impact process, which discloses impacts from projects, but
provides no regulatory protection for State-listed plants on private
lands.
Florida Statutes 581.185 sections (3)(a) and (b) prohibit any
person from willfully destroying or harvesting any species listed as
endangered or threatened on the Index, or growing such a plant on the
private land of another, or on any public land, without first obtaining
the written permission of the landowner and a permit from the Florida
Department of Plant Industry. The statute further provides that any
person willfully destroying or harvesting; transporting, carrying, or
conveying on any public road or highway; or selling or offering for
sale any plant listed in the Index as endangered must have a permit
from the State at all times when engaged in any such activities.
In addition, subsections (8)(a) and (b) of the statute waive State
regulation for certain classes of activities for all species on the
Regulated Plant Index, including the clearing or removal of regulated
plants for agricultural, forestry, mining, construction (residential,
commercial, or infrastructure), and fire-control activities by a
private landowner or his or her agent. However, section (10) of the
statute provides for consultation similar to section 7 of the Federal
Act for listed species by requiring the Department of Transportation to
notify the FDACS and the Endangered Plant Advisory Council of planned
highway construction at the time bids are first advertised, to
facilitate evaluation of the project for listed plant populations, and
to ``provide for the appropriate disposal of such plants'' (i.e.,
transplanting).
Local
In 1984, Section 24-49 of the Code of Miami-Dade County established
regulation of County-designated NFCs, which include both pine rocklands
and tropical hardwood hammocks. These regulations were placed on
specific properties throughout the county by an act of the Board of
County Commissioners in an effort to protect environmentally sensitive
forest lands. The Miami-Dade County Department of Regulatory and
Economic Resources (RER) has regulatory authority over NFCs and is
charged with enforcing regulations that provide partial protection on
the Miami Rock Ridge. Miami-Dade Code typically allows up to 20 percent
of a pine rockland designated as NFC to be developed, and requires that
the remaining 80 percent be placed under a perpetual covenant. In
certain circumstances, where the landowner can demonstrate that
limiting development to 20 percent does not allow for ``reasonable
use'' of the property, additional development may be approved. NFC
landowners are also required to obtain an NFC permit for any work,
including removal of nonnatives within the boundaries of the NFC on
their property. The NFC program is responsible for ensuring that NFC
permits are issued in accordance with the limitations and requirements
of the code and that appropriate NFC preserves are established and
maintained in conjunction with the issuance of an NFC permit. The NFC
program currently regulates approximately 600 pine rockland or pine
rockland/hammock properties, comprising approximately 1,200 ha (3,000
ac) of habitat (Joyner 2013, pers. comm.). NFC regulations are designed
to prevent clearing or destruction of native vegetation within
preserved areas; however, illegal development and destruction of pine
rockland continues to occur, despite these regulations. When
discovered, RER pursues unpermitted work through appropriate
enforcement action and seeks restoration when possible.
Fee Title Properties
In 1990, Miami-Dade County voters approved a 2-year property tax to
fund the acquisition, protection, and maintenance of environmentally
endangered lands. The EEL Program identifies and secures these lands
for preservation. Under this program to date, Miami-Dade County has
acquired a total of approximately 255 ha (630 ac) of pine rockland. In
addition, approximately 445 ha (1,100 ac) of pine rockland are owned by
the Miami-Dade County Parks and Recreation Department and managed by
the EEL Program, including some of the largest remaining areas of pine
rockland habitat on the Miami Rock Ridge outside of ENP (e.g., Larry
and Penny Thompson Park, Zoo Miami pinelands, and Navy Wells Pineland
Preserve).
While State and local regulations, and fee title properties, do
provide for protection of these plants specifically, and pine rockland
habitat in general, they are either not effective or not implemented
sufficiently to alleviate the threats to these plants or their habitat.
E. Other Natural or Manmade Factors Affecting Its Continued Existence
Brickellia mosieri and Linum carteri var. carteri are both
threatened by other natural or manmade factors that affect each taxon
to varying degrees. Specific threats to these plants included in this
factor consist of the spread of nonnative invasive plants, potentially
incompatible management practices (such as mowing and herbicide use),
direct impacts to plants from recreation and other human activities,
small population size and isolation, climate change, and the related
risks from environmental stochasticity (extreme weather) on these small
populations. Each of these threats and its specific effect on these
plants are discussed in detail below.
[[Page 61286]]
Nonnative Plant Species
Nonnative plants have significantly affected pine rocklands, and
threaten all occurrences of Brickellia mosieri and Linum carteri var.
carteri to some degree (Bradley and Gann 1999, pp. 15, 72; Bradley and
Gann 2005, page numbers not applicable; Bradley 2007, pers. comm.;
Bradley and van der Heiden 2013, pp. 12-16). As a result of human
activities, at least 277 taxa of nonnative plants have invaded pine
rocklands throughout south Florida (Service 1999, p. 3-175). Neyraudia
neyraudiana (Burma reed) and Schinus terebinthifolius (Brazilian
pepper) threaten both plants (Bradley and Gann 1999, pp. 13, 72). S.
terebinthifolius, a nonnative tree, is the most widespread and one of
the most invasive species. It forms dense thickets of tangled, woody
stems that completely shade out and displace native vegetation (Loflin
1991, p. 19; Langeland and Craddock Burks 1998, p. 54). Acacia
auriculiformis (earleaf acacia), Rhynchelytrum repens (natal grass),
Lantana camara (shrub verbena), and Albizia lebbeck (tongue tree) are
some of the other nonnative species in pine rocklands. More species of
nonnative plants could become problems in the future, such as Lygodium
microphyllum (Old World climbing fern), which is a serious threat
throughout south Florida.
Nonnative invasive plants compete with native plants for space,
light, water, and nutrients, and make habitat conditions unsuitable for
both Brickellia mosieri and Linum carteri var. carteri, which respond
positively to open conditions. They also affect the characteristics of
a fire when it does occur. Historically, pine rocklands had an open,
low understory where natural fires remained patchy with low temperature
intensity, thus sparing many native plants such as B. mosieri and L. c.
var. carteri. Dense infestations of Neyraudia neyraudiana and Schinus
terebinthifolius cause higher fire temperatures and longer burning
periods. With the presence of invasive nonnative species, it is
uncertain how fire, even under a managed situation, will affect these
plants. Bradley and Gann (1999, pp. 13, 71-72) indicated that the
control of nonnative plants is one of the most important conservation
actions for these plants and a critical part of habitat maintenance.
Management of nonnative invasive plants in pine rocklands in Miami-
Dade County is further complicated because the vast majority of pine
rocklands are small, fragmented areas bordered by urban development.
Areas near managed pine rockland that contain nonnative species can act
as a seed source of nonnatives allowing them to continue to invade the
surrounding pine rockland (Bradley and Gann 1999, p. 13).
Mowing
Linum carteri var. carteri's occurrence in disturbed, open areas
such as firebreaks and road rights-of-way makes it much more
susceptible than Brickellia mosieri to disturbance factors such as
mowing. According to Bradley and van der Heiden (2013, pp. 12-16), five
of the seven extant populations of this variety are vulnerable to
changes in mowing practices. Mowing can serve to maintain an open
understory in the absence of fire (Bradley and Gann 1999, p. 71;
Maschinski and Walters 2007, p. 56). For example, at the Montgomery
Botanical Center, occasional mowing is thought to keep competing
vegetation at bay while still allowing the plants to complete their
life cycle (Maschinski 2011, pers. comm.). However, mowing can also
threaten this variety depending on the timing, frequency, and intensity
of its application (see Status Assessment, above). If not properly
applied, mowing can eliminate reproduction entirely in very young
plants or delay reproductive maturation (Maschinski and Walters 2007,
p. 56; 2008, p. 28). In some instances, adult plants may be killed, but
typically mowing simply disrupts the apical meristem (as with natural
levels of herbivory) and triggers production of additional lateral
branches; plants can produce compensatory branches following mowing and
live to reproduce at a later time as long as the mowing regime is not
too frequent (Maschinski and Walters 2008, p. 28). The impact of mowing
can be modified by the timing and frequency of the mowing event,
rainfall prior to and following the event, and the numbers of plants
that have reached reproductive state prior to mowing (Maschinski and
Walters 2008, p. 27). Maschinski and Walters (2008, p. 28) recommended
adjusting the timing of mowing to occur at least three weeks after
flowering is observed to allow a higher probability of adults setting
fruit prior to the mowing event. With flexibility and proper
instructions to land managers and ground crews, mowing practices could
be implemented in such a way as to scatter seeds and reduce competition
with little effect on population reproductive output for the year
(Maschinski and Walters 2008, p. 28).
Herbicides
As with mowing, the use of herbicides is more likely to threaten
populations of Linum carteri var. carteri, due to the variety's
occurrence in disturbed, open areas, which are also the typical habitat
of weedy and nonnative plant species. Two of the seven extant L. c.
var. carteri occurrences--the C-103 Canal and Chapman Field USDA
Subtropical Horticultural Research Station--are in such areas. The use
of herbicides for weed control here would be detrimental to these
populations.
Recreation and Other Human Activities
Linum carteri var. carteri's occurrence in disturbed, open areas
such as firebreaks and road rights-of-way also makes it much more
susceptible than Brickellia mosieri to recreational and other human
activities. These activities may inadvertently impact some populations
of L. c. var. carteri. In the past, mountain biking has been identified
as a threat at R. Hardy Matheson Preserve (Bradley and Gann 1999, pp.
71, 74; Bradley 2007, pers. comm.), but this was remedied by placement
of protective fencing (Possley 2012, pers. comm.). More recently, a
colony of L. c. var. carteri at Camp Owaissa Bauer Addition has been
impacted by ``yard sales'' and car parking along Krome Avenue (Bradley
and van der Heiden 2013, p. 13). While these impacts are usually some
distance from the plants, they sometimes encroach on the edge of the
natural area and have the potential to trample the plants. This plant
occurs in similar habitat on Rockdale Pineland, where it is found along
the edges of the abandoned FEC Railroad tracks, adjacent to pine
rockland habitat (Bradley and van der Heiden 2013, p. 16). Here, plants
have also been trampled from parking vehicles and machinery along the
edges of the railroad right-of-way (Bradley and van der Heiden 2013, p.
16). While these activities have affected individual plants in some
populations, they are not likely to have caused significant population
declines in the taxon.
Effects of Small Population Size and Isolation
Endemic species whose populations exhibit a high degree of
isolation are extremely susceptible to extinction from both random and
nonrandom catastrophic natural or human-caused events. Species that are
restricted to geographically limited areas are inherently more
vulnerable to extinction than widespread species because of the
increased risk of genetic bottlenecks, random demographic fluctuations,
climate change, and localized catastrophes such as hurricanes and
disease outbreaks (Mangel and Tier
[[Page 61287]]
1994, p. 607; Pimm et al. 1988, p. 757). These problems are further
magnified when populations are few and restricted to a very small
geographic area, and when the number of individuals is very small.
Populations with these characteristics face an increased likelihood of
stochastic extinction due to changes in demography, the environment,
genetics, or other factors (Gilpin and Soule 1986, pp. 24-34).
Small, isolated populations, such as those in fragmented habitat,
often exhibit reduced levels of genetic variability, although the
ultimate effect of these changes is dependent on a plant's specific
life history, reproductive system, and interaction with pollinators and
dispersal vectors (which may themselves be affected by fragmentation)
(Young et al. 1996, p. 413). While research results clearly indicate
that isolation/fragmentation has population genetic consequences for
plants, consequences are varied and for some species there may be a
``fragmentation threshold'' below which genetic variation is not lost
(Young et al. 1996, p. 416). No such study has been conducted for
Brickellia mosieri or Linum carteri var. carteri, so whether these
plants exhibit such a threshold is not known. Reduced genetic
variability generally diminishes a species' capacity to adapt and
respond to environmental changes, thereby decreasing the probability of
long-term persistence (e.g., Barrett and Kohn 1991, p. 4; Newman and
Pilson 1997, p. 361). Very small plant populations may experience
reduced reproductive vigor due to ineffective pollination or inbreeding
depression. Isolated individuals have difficulty achieving natural
pollen exchange, which limits the production of viable seed. The
problems associated with small population size and vulnerability to
random demographic fluctuations or natural catastrophes are further
magnified by synergistic (interaction of two or more components)
effects with other threats, such as those discussed above.
Only small and fragmented occurrences of these two plants remain.
The current ranges of Brickellia mosieri and Linum carteri var. carteri
span such a small geographic area--a narrow band (no more than 4.0 km
(2.5 mi) in width) along the ridge approximately 30.1 km (18.7 mi) and
26.9 km (16.7 mi) in length, respectively--that all populations could
be affected by a single event (e.g., hurricane). Four of the seven
remaining populations of L. c. var. carteri have fewer than 20
individual plants (see Table 2). B. mosieri populations occur in higher
numbers (Table 1) but are still not considered sizable. L. c. var.
carteri shows great differences in plant numbers from year to year,
probably because individuals typically live 1-2 years and grow from
seed. This trait makes them more vulnerable than perennials to changes
in environment. Viable plant populations for small, short-lived herbs
may consist of tens of thousands of plants (Menges 1991, p. 48; Lande
1995, p. 789). Although robust population viability analyses (including
minimum viable population calculations) have not been conducted for
these plants, indications are that most existing populations for both
plants are at best marginal. Lack of dispersal between occurrences may
also be a threat (see Habitat Fragmentation under Factor A).
Climate Change
Climatic changes, including sea level rise (SLR), are major threats
to south Florida, including Brickellia mosieri and Linum carteri var.
carteri. Our analyses under the Act include consideration of ongoing
and projected changes in climate. The terms ``climate'' and ``climate
change'' are defined by the Intergovernmental Panel on Climate Change
(IPCC). The term ``climate'' refers to the mean and variability of
different types of weather conditions over time, with 30 years being a
typical period for such measurements, although shorter or longer
periods also may be used (IPCC 2007, p. 78). The term ``climate
change'' thus refers to a change in the mean or variability of one or
more measures of climate (e.g., temperature or precipitation) that
persists for an extended period, typically decades or longer, whether
the change is due to natural variability, human activity, or both (IPCC
2007, p. 78).
Scientific measurements spanning several decades demonstrate that
changes in climate are occurring, and that the rate of change has been
faster since the 1950s. Examples include warming of the global climate
system, and substantial increases in precipitation in some regions of
the world and decreases in other regions. (For these and other
examples, see IPCC 2007, p. 30; and Solomon et al. 2007, pp. 35-54, 82-
85.)
Scientists use a variety of climate models, which include
consideration of natural processes and variability, as well as various
scenarios of potential levels and timing of greenhouse gas (GHG)
emissions, to evaluate the causes of changes already observed and to
project future changes in temperature and other climate conditions
(e.g., Meehl et al. 2007, entire; Ganguly et al. 2009, pp. 11555,
15558; Prinn et al. 2011, pp. 527, 529). Although projections of the
magnitude and rate of warming differ after about 2030, the overall
trajectory of all the projections is one of increased global warming
through the end of this century, even for the projections based on
scenarios that assume that GHG emissions will stabilize or decline.
Thus, there is strong scientific support for projections that warming
will continue through the 21st century, and that the magnitude and rate
of change will be influenced substantially by the extent of GHG
emissions (IPCC 2007, pp. 44-45; Meehl et al. 2007, pp. 760-764 and
797-811; Ganguly et al. 2009, pp. 15555-15558; Prinn et al. 2011, pp.
527, 529).
Various changes in climate may have direct or indirect effects on
species. These effects may be positive, neutral, or negative, and they
may change over time, depending on the species and other relevant
considerations, such as interactions of climate with other variables
(e.g., habitat fragmentation) (IPCC 2007, pp. 8-14, 18-19).
Projected changes in climate and related impacts can vary
substantially across and within different regions of the world (e.g.,
IPCC 2007, pp. 8-12). Therefore, we use ``downscaled'' projections when
they are available and have been developed through appropriate
scientific procedures (see Glick et al. 2011, pp. 58-61, for a
discussion of downscaling). With regard to our analysis for Brickellia
mosieri and Linum carteri var. carteri, downscaled projections suggest
that SLR is the largest climate-driven challenge to low-lying coastal
areas in the subtropical ecoregion of southern Florida (U.S. Climate
Change Science Program (USCCSP) 2008, pp. 5-31, 5-32). Several
populations of B. mosieri occur at elevations less than 2 m (6.6 ft)
above sea level. In addition, approximately 50 percent of the known
occurrences of L. c. var. carteri are located along a coastal ridge,
making the species highly susceptible to increased storm surges and
related impacts associated with SLR.
The long-term record at Key West shows that sea level rose on
average 0.229 cm (0.090 in) annually between 1913 and 2013 (National
Oceanographic and Atmospheric Administration (NOAA) 2013, p. 1). This
equates to approximately 22.9 cm (9.02 in) over the last 100 years.
IPCC (2008, p. 28) emphasized it is very likely that the average rate
of SLR during the 21st century will exceed the historical rate. The
IPCC Special Report on Emission Scenarios (2000, entire) presented a
range of scenarios based on the computed amount of change in the
climate system due to various potential
[[Page 61288]]
amounts of anthropogenic greenhouse gases and aerosols in 2100. Each
scenario describes a future world with varying levels of atmospheric
pollution leading to corresponding levels of global warming and
corresponding levels of SLR. The IPCC Synthesis Report (2007, entire)
provided an integrated view of climate change and presented updated
projections of future climate change and related impacts under
different scenarios.
Subsequent to the 2007 IPCC Report, the scientific community has
continued to model SLR. Recent peer-reviewed publications indicate a
movement toward increased acceleration of SLR. Observed SLR rates are
already trending along the higher end of the 2007 IPCC estimates, and
it is now widely held that SLR will exceed the levels projected by the
IPCC (Rahmstorf et al. 2012, p. 1; Grinsted et al. 2010, p. 470). Taken
together, these studies support the use of higher end estimates now
prevalent in the scientific literature. Recent studies have estimated
global mean SLR of 1-2 m (3.3-6.6 ft) by 2100 as follows: 0.75-1.90 m
(2.5-6.2 ft; Vermeer and Rahmstorf 2009, p. 21530), 0.8-2.0 m (2.6-6.6
ft; Pfeffer et al. 2008, p. 1342), 0.9-1.3 m (3.0-4.3 ft; Grinsted et
al. 2010, pp. 469-470), 0.6-1.6 m (2.0-5.2 ft; Jevrejeva et al. 2010,
p. 4), and 0.5-1.40 m (1.6-4.6 ft; National Resource Council 2012, p.
2).
Other processes expected to be affected by projected warming
include temperatures, rainfall (amount, seasonal timing, and
distribution), and storms (frequency and intensity) (discussed more
specifically under Environmental Stochasticity, below). The
Massachusetts Institute of Technology (MIT) modeled several scenarios
combining various levels of SLR, temperature change, and precipitation
differences with human population growth, policy assumptions, and
conservation funding changes (see Alternative Future Landscape Models,
below). All of the scenarios, from small climate change shifts to major
changes, indicate significant effects on coastal Miami-Dade County.
Prior to inundation, pine rocklands are likely to undergo habitat
transitions related to climate change, including changes to hydrology
and increasing vulnerability to storm surge. Hydrology has a strong
influence on plant distribution in these and other coastal areas (IPCC
2008, p. 57). Such communities typically grade from salt to brackish to
freshwater species. From the 1930s to 1950s, increased salinity of
coastal waters contributed to the decline of cabbage palm forests in
southwest Florida (Williams et al. 1999, pp. 2056-2059), expansion of
mangroves into adjacent marshes in the Everglades (Ross et al. 2000,
pp. 101, 111), and loss of pine rockland in the Keys (Ross et al. 1994,
pp. 144, 151-155). In one Florida Keys pine rockland with an average
elevation of 0.89 m (2.9 ft), Ross et al. (1994, pp. 149-152) observed
an approximately 65 percent reduction in an area occupied by South
Florida slash pine over a 70-year period, with pine mortality and
subsequent increased proportions of halophytic (salt-loving) plants
occurring earlier at the lower elevations. During this same timespan,
local sea level had risen by 15 cm (6.0 in), and Ross et al. (1994, p.
152) found evidence of groundwater and soil water salinization.
Extrapolating this situation to pine rocklands on the mainland is not
straightforward, but suggests that similar changes to species
composition could arise if current projections of SLR occur and
freshwater inputs are not sufficient to prevent salinization.
Furthermore, Ross et al. (2009, pp. 471-478) suggested that
interactions between SLR and pulse disturbances (e.g., storm surges)
can cause vegetation to change sooner than projected based on sea level
alone. Alexander (1953, pp. 133-138) attributed the demise of pinelands
on northern Key Largo to salinization of the groundwater in response to
SLR. Patterns of human development will also likely be significant
factors influencing whether natural communities can move and persist
(IPCC 2008, p. 57; USCCSP 2008, p. 7-6).
The Science and Technology Committee of the Miami-Dade County
Climate Change Task Force (Wanless et al. 2008, p. 1) recognizes that
significant SLR is a very real threat to the near future for Miami-Dade
County. In a January 2008 statement, the committee warned that sea
level is expected to rise at least 0.9-1.5 m (3-5 ft) within this
century (Wanless et al. 2008, p. 3). With a 0.9-1.2 m (3-4 ft) rise in
sea level (above baseline) in Miami-Dade County: ``Spring high tides
would be at about 6 to 7 feet; freshwater resources would be gone; the
Everglades would be inundated on the west side of Miami-Dade County;
the barrier islands would be largely inundated; storm surges would be
devastating; landfill sites would be exposed to erosion contaminating
marine and coastal environments. Freshwater and coastal mangrove
wetlands will not keep up with or offset SLR of 2 ft per century or
greater. With a 5-ft rise (spring tides at nearly +8 ft), Miami-Dade
County will be extremely diminished'' (Wanless et al. 2008, pp. 3-4).
Drier conditions and increased variability in precipitation
associated with climate change are expected to hamper successful
regeneration of forests and cause shifts in vegetation types through
time (Wear and Greis 2012, p. 39). Although it has not been well
studied, existing pine rocklands have probably been affected by
reductions in the mean water table. Climate changes are also forecasted
to extend fire seasons and the frequency of large fire events
throughout the Coastal Plain (Wear and Greis 2012, p. 43). While
restoring fire to pine rocklands is essential to the long-term
viability of Brickellia mosieri and Linum carteri var. carteri
populations, increases in the scale, frequency, or severity of
wildfires could have negative effects on these plants considering their
general vulnerability due to small population size, restricted range,
few colonies, and relative isolation.
Alternative Future Landscape Models
To accommodate the large uncertainty in SLR projections,
researchers must estimate effects from a range of scenarios. Various
model scenarios developed at MIT and GeoAdaptive Inc. have projected
possible trajectories of future transformation of the south Florida
landscape by 2060 based upon four main drivers: climate change, shifts
in planning approaches and regulations, human population change, and
variations in financial resources for conservation (Vargas-Moreno and
Flaxman 2010, pp. 1-6). The scenarios do not account for temperature,
precipitation, or species habitat shifts due to climate change, and no
storm surge effects are considered. The current MIT scenarios range
from an increase of 0.09-1.0 m (0.3-3.3 ft) by 2060.
Based on the most recent estimates of SLR and the data available to
us at this time, we evaluated potential effects of SLR using the
current ``high'' range MIT scenario as well as comparing elevations of
remaining pine rockland fragments and extant and historical occurrences
of Brickellia mosieri and Linum carteri var. carteri occurrences. The
``high'' range (or ``worst case'') MIT scenario assumes high SLR (1 m
(3.3 ft) by 2060), low financial resources, a `business as usual'
approach to planning, and a doubling of human population. Based on this
scenario, pine rocklands along the coast in central Miami-Dade County,
including one occurrence of L. c. var. carteri at R. Hardy Matheson
Preserve, would become inundated. The ``new'' sea level would come up
to the edge of pine rockland fragments at the southern end as well,
translating to partial inundation or, at a minimum, vegetation
[[Page 61289]]
shifts in the pine rocklands in and around Navy Wells. While sea level
would not overtake other pine rocklands in urban Miami-Dade County,
changes in the salinity of the water table and soils would surely cause
vegetation shifts in additional areas. In addition, many existing pine
rockland fragments are projected to be developed for housing as the
human population grows and adjusts to changing sea levels under this
scenario. Actual impacts may be greater or less than anticipated based
upon high variability of factors involved (e.g., SLR, human population
growth) and assumptions made.
When simply looking at current elevations of pine rockland
fragments and occurrences of these plants, it appears that an SLR of 1
m (3.3. ft) will inundate the coastal and southern pine rocklands and
cause vegetation shifts largely as described above. SLR of 2 m (6.6 ft)
appears to inundate much larger portions of urban Miami-Dade County,
including all of Navy Wells and its surrounding area, and with it,
several extant occurrences of Brickellia mosieri. The western part of
urban Miami-Dade County would also be inundated (barring creation of
sea walls or other barriers), creating a virtual island of the Miami
Rock Ridge. After a 2-m rise in sea level, approximately 75 percent of
the remaining pine rockland would still be above sea level but an
unknown percentage of these fragments would be negatively impacted by
salinization of the water table and soils, which would be exacerbated
due to isolation from mainland fresh water flows. Above 2 m (6.6 ft) of
SLR, very little pine rockland would remain, with the vast majority
either being inundated or experiencing vegetation shifts.
Environmental Stochasticity
The climate of southern Florida is driven by a combination of
local, regional, and global events, regimes, and oscillations. There
are three main ``seasons'': (1) the wet season, which is hot, rainy,
and humid from June through October; (2) the official hurricane season
that extends one month beyond the wet season (June 1 through November
30), with peak season being August and September; and (3) the dry
season, which is drier and cooler, from November through May. In the
dry season, periodic surges of cool and dry continental air masses
influence the weather with short-duration rain events followed by long
periods of dry weather.
According to the Florida Climate Center, Florida is by far the most
vulnerable State in the United States to hurricanes and tropical storms
(http://coaps.fsu.edu/climate_center/tropicalweather.shtml). Based on
data gathered from 1856 to 2008, Klotzbach and Gray (2009, p. 28)
calculated the climatological probabilities for each State being
impacted by a hurricane or major hurricane in all years over the 152-
year timespan. Of the coastal States analyzed, Florida had the highest
climatological probabilities, with a 51 percent probability of a
hurricane (Category 1 or 2) and a 21 percent probability of a major
hurricane (Category 3 or higher). From 1856 to 2008, Florida actually
experienced 109 hurricanes and 36 major hurricanes. Given the low
population sizes and restricted ranges of Brickellia mosieri and Linum
carteri var. carteri, and the few isolated occurrences of L. c. var.
carteri within locations prone to storm influences, these plants are at
substantial risk from hurricanes, storm surges, and other extreme
weather. Depending on the location and intensity of a hurricane or
other severe weather event, it is possible that these plants could
become extirpated or extinct.
Hurricanes, storm surge, and extreme high tide events are natural
events that can pose a threat to both plants. Hurricanes and tropical
storms can modify habitat (e.g., through storm surge) and have the
potential to destroy entire populations. Climate change may lead to
increased frequency and duration of severe storms (Golladay et al.
2004, p. 504; McLaughlin et al. 2002, p. 6074; Cook et al. 2004, p.
1015). Both plants experienced these disturbances historically, but had
the benefit of more abundant and contiguous habitat to buffer them from
extirpations. With most of the historical habitat having been destroyed
or modified, the few remaining populations of these plants could face
local extirpations due to stochastic events.
Other processes to be affected by climate change, related to
environmental stochasticity, include temperatures, rainfall (amount,
seasonal timing, and distribution), and storms (frequency and
intensity). Temperatures are projected to rise from 2-5 [deg]C (3.6-9
[deg]F) for North America by the end of this century (IPCC 2007, pp. 7-
9, 13). Based upon modeling, Atlantic hurricane and tropical storm
frequencies are expected to decrease (Knutson et al. 2008, pp. 1-21).
By 2100, there should be a 10-30 percent decrease in hurricane
frequency. Hurricane frequency is expected to drop due to more wind
shear impeding initial hurricane development. However, hurricane winds
are expected to increase by 5-10 percent. This is due to more hurricane
energy available for intense hurricanes. In addition to climate change,
weather variables are extremely influenced by other natural cycles,
such as El Ni[ntilde]o Southern Oscillation with a frequency of every
4-7 years, solar cycle (every 11 years), and the Atlantic Multi-decadal
Oscillation. All of these cycles influence changes in Floridian
weather. The exact magnitude, direction, and distribution of all of
these changes at the regional level are difficult to project.
Freezing Temperatures
Occasional freezing temperatures that occur in south Florida are a
threat to Brickellia mosieri and Linum carteri var. carteri, causing
damage or death to individual plants. Under normal circumstances,
occasional freezing temperatures would not result in a significant
impact to populations of these plants; however, the small size of some
populations means the loss from freezing events of even a few
individuals can reduce the viability of the population.
Conservation Efforts To Reduce Other Natural or Manmade Factors
Affecting Continued Existence
An IRC program included reintroduction of both Brickellia mosieri
and Linum carteri var. carteri in an effort to establish new
occurrences of these plants and increase population sizes. To date, B.
mosieri has been reintroduced to at least one site (George and Avery
Pineland), although the status of these plants is currently unknown
(Gann 2013b, pers. comm.).
Ex-situ conservation by FTBG consists of seed collection of pine
rockland plants, including Brickellia mosieri and Linum carteri var.
carteri, to learn about their germination, storage, and cultivation
requirements to help safeguard these plants from extinction. FTBG has
22 seed accessions of B. mosieri, and a total of 1,589 seeds were
provided to the National Center for Genetic Resources Preservation
(NGRCP) for long-term storage (Maschinski et al. 2009, p. 26). Of L. c.
var. carteri, FTBG has 59 accessions, and 2,643 seeds were provided to
NGRCP for long-term storage (Maschinski et al. 2009, p. 27). Maschinski
et al. (2009, p. 19 and 21) indicate that both plants are capable of
orthodox seed storage. Frozen B. mosieri seeds germinated at 55 percent
after 1 week of storage, compared to 54 percent of fresh seeds and 40
percent of desiccated seeds (Maschinski et al. 2009, p. 19). Frozen L.
c. var. carteri seeds germinated at 75 percent after 4 months of
storage, compared to 69 percent of fresh seeds and 71-88
[[Page 61290]]
percent of desiccated seeds (Maschinski et al. 2009, p. 21). These
results indicate that seed storage may be a useful strategy for future
reintroductions and supplementation of existing populations to increase
the numbers and sizes of populations of these plants. As part of FTBG's
Connect To Protect Network, reintroduction of endemic pine rockland
plants such as B. mosieri and L. c. var. carteri is planned in
corridors (networks of private stepping-stone gardens and public
rights-of-way) they hope to create.
Cumulative Effects of Threats
The limited distributions and small population sizes of Brickellia
mosieri and Linum carteri var. carteri make them extremely susceptible
to further habitat loss, modification, and degradation and other
anthropogenic threats. Mechanisms leading to the decline of these
plants, as discussed above, range from local (e.g., lack of adequate
fire management, mowing, herbicides), to regional (e.g., development,
fragmentation, nonnative species), to global influences (e.g., climate
change, SLR). The synergistic effects of threats (such as hurricane
effects on a species with a limited distribution consisting of just a
few small populations) make it difficult to predict population
viability. While these stressors may act in isolation, it is more
probable that many stressors are acting simultaneously (or in
combination) on populations of B. mosieri and L. c. var. carteri.
Summary of Threats
We have determined that the threats to both Brickellia mosieri and
Linum carteri var. carteri consist primarily of habitat loss and
modification through urban and agricultural development, lack of
adequate fire management, proliferation of nonnative invasive plants,
and SLR. Threats described under Factor A--habitat loss, fragmentation,
and degradation resulting from development and inadequate fire
management, and Factor E--competition from nonnative invasive plants,
are believed to be the primary drivers in the historical and recent
declines of B. mosieri and L. c. var. carteri. L. c. var. carteri has
also been threatened by anthropogenic disturbances which threaten
populations in disturbed habitats, such as firebreaks and road rights-
of-way, and both plants are suspected to be negatively affected by
threats related to small, isolated populations (Factor E). All of these
threats are expected to continue to impact populations of these plants
in the future. Current local, State, and Federal regulatory mechanisms
(Factor D) are inadequate to protect these plants from taking and
habitat loss. Despite the existing regulatory mechanisms, B. mosieri
and L. c. var. carteri continue to decline.
Other factors that are likely to threaten Brickellia mosieri and
Linum carteri var. carteri in the future are climate change (including
SLR) and extreme weather events (hurricanes, frost events), especially
as effects of these could be catastrophic on isolated, small
populations of both plants (Factor E). The majority of the remaining
populations of these plants are generally small and geographically
isolated. The narrow distribution of their populations in hurricane-
prone south Florida makes them more susceptible to extirpation from a
single catastrophic event. Furthermore, this level of isolation makes
natural recolonization of extirpated populations virtually impossible
without human intervention.
The above-described threats have had substantial adverse effects on
Brickellia mosieri and Linum carteri var. carteri populations and their
habitats. Although attempts are ongoing to alleviate some of these
threats at some locations, no populations appear to be without one or
more major threats.
Proposed Determination
We have carefully assessed the best scientific and commercial
information available regarding the past, present, and future threats
to Brickellia mosieri and Linum carteri var. carteri. Section 3(6) of
the Act defines an endangered species as ``any species which is in
danger of extinction throughout all or a significant portion of its
range'' and section 3(20) of the Act defines a threatened species as
``any species which is likely to become an endangered species within
the foreseeable future throughout all or a significant portion of its
range.''
As described in detail above, both plants are currently at risk
throughout all of their respective ranges due to the immediacy,
severity, and scope of threats from habitat destruction and
modification (Factor A) and other natural or manmade factors affecting
their continued existence (Factor E), and existing regulatory
mechanisms are inadequate to reduce these threats (Factor D). Although
actions are ongoing to alleviate some threats, no populations appear to
be free of major threats. As a result, impacts from increasing threats,
singly or in combination, are likely to result in the extinction of
these plants.
Brickellia mosieri
Brickellia mosieri has been extirpated from approximately 13
percent of its historical range, and the primary threats of inadequate
fire management (Factor A) and competition from nonnative invasive
plants (Factor E) are currently active in the remaining populations.
Populations of B. mosieri are relatively small and isolated from one
another, and the species' ability to recolonize suitable habitat
between populations is unknown at this time. Because of the current
condition of the populations and life-history traits of the species, it
is vulnerable to natural or human-caused changes in its currently
occupied habitats. Existing regulatory mechanisms are inadequate to
eliminate or even reduce these threats (Factor D). Numerous threats are
occurring now and are likely to continue in the foreseeable future, at
a high intensity, and across the species' entire range; therefore, we
have determined the species is currently on the brink of extinction.
Because these threats are placing the species in danger of extinction
now and not only at some point in the foreseeable future, we find this
species meets the definition of an endangered species rather than a
threatened species. Therefore, we are proposing to list it as an
endangered species. These threats are currently active, and will
continue to affect the populations of B. mosieri into the foreseeable
future, and these threats will individually and collectively contribute
to the species' local extirpation and potential extinction.
Linum carteri var. carteri
L. c. var. carteri has been extirpated from approximately 30
percent of its historical range, and threats of inadequate fire
management (Factor A) and competition from nonnative, invasive plants
(Factor E), as well as other anthropogenic disturbances (Factor E), are
currently active in the remaining populations. Populations of L. c.
var. carteri are small, few in number, and isolated from one another;
the taxon's ability to recolonize suitable habitat between populations
is unknown at this time. Because of the current condition of the
populations and life-history traits of the taxon, it is vulnerable to
natural or human-caused changes in its currently occupied habitats.
Existing regulatory mechanisms are inadequate to eliminate or even
reduce these threats (Factor D). Numerous threats are occurring now and
are likely to continue in the foreseeable future, at a high intensity,
and across the taxon's entire range;
[[Page 61291]]
therefore, we have determined the taxon is currently on the brink of
extinction. Because these threats are placing the taxon in danger of
extinction now and not only at some point in the foreseeable future, we
find this taxon meets the definition of an endangered species rather
than a threatened species. Therefore, we are proposing to list it as an
endangered species. The threats described above are currently active,
and will continue to affect the populations of L. c. var. carteri into
the foreseeable future, and these threats will individually and
collectively contribute to the taxon's local extirpation and potential
extinction.
Significant Portion of Its Range
We evaluated the current ranges of Brickellia mosieri and Linum
carteri var. carteri to determine if there is any apparent geographic
concentration of potential threats for either taxon. Both plants are
highly restricted in their ranges, and the threats occur throughout
their ranges. We considered the potential threats due to habitat loss
and modification from development, lack of adequate fire management,
competition from nonnative plants, and SLR, as well as the threats of
incompatible land management and other human activities, hurricanes and
other extreme weather, and small populations with restricted range. We
found no concentration of threats because of the plants' limited and
curtailed ranges, and uniformity of the threats throughout their entire
ranges. Having determined that B. mosieri and L. c. var. carteri are
endangered throughout their entire ranges, it is not necessary to
evaluate whether there are any significant portions of their ranges.
Available Conservation Measures
Conservation measures provided to species listed as endangered or
threatened under the Act include recognition, recovery actions,
requirements for Federal protection, and prohibitions against certain
practices. Recognition through listing results in public awareness and
conservation by Federal, State, Tribal, and local agencies; private
organizations; and individuals. The Act encourages cooperation with the
States and requires that recovery actions be carried out for all listed
species. The protection required by Federal agencies and the
prohibitions against certain activities are discussed, in part, below.
The primary purpose of the Act is the conservation of endangered
and threatened species and the ecosystems upon which they depend. The
ultimate goal of such conservation efforts is the recovery of these
listed species, so that they no longer need the protective measures of
the Act. Subsection 4(f) of the Act requires the Service to develop and
implement recovery plans for the conservation of endangered and
threatened species. The recovery planning process involves the
identification of actions that are necessary to halt or reverse the
species' decline by addressing the threats to its survival and
recovery. The goal of this process is to restore listed species to a
point where they are secure, self-sustaining, and functioning
components of their ecosystems.
Recovery planning includes the development of a recovery outline
shortly after a species is listed, preparation of a draft and final
recovery plan, and revisions to the plan as significant new information
becomes available. The recovery outline guides the immediate
implementation of urgent recovery actions and describes the process to
be used to develop a recovery plan. The recovery plan identifies site-
specific management actions that will achieve recovery of the species,
measurable criteria that determine when a species may be downlisted or
delisted, and methods for monitoring recovery progress. Recovery plans
also establish a framework for agencies to coordinate their recovery
efforts and provide estimates of the cost of implementing recovery
tasks. Recovery teams (comprising species experts, Federal and State
agencies, nongovernmental organizations, and stakeholders) are often
established to develop recovery plans. When completed, the recovery
outline, draft recovery plan, and the final recovery plan will be
available on our Web site (http://www.fws.gov/endangered), or from our
South Florida Ecological Services Field Office (see FOR FURTHER
INFORMATION CONTACT).
Implementation of recovery actions generally requires the
participation of a broad range of partners, including other Federal
agencies, States, Tribal, nongovernmental organizations, businesses,
and private landowners. Examples of recovery actions include habitat
restoration (e.g., restoration of native vegetation), research, captive
propagation and reintroduction, and outreach and education. The
recovery of many listed species cannot be accomplished solely on
Federal lands because their range may occur primarily or solely on non-
Federal lands. To achieve recovery of these plants requires cooperative
conservation efforts on private, State, and Tribal lands.
If these plants are listed, funding for recovery actions will be
available from a variety of sources, including Federal budgets, State
programs, and cost-share grants for non-Federal landowners, the
academic community, and nongovernmental organizations. In addition,
under section 6 of the Act, the State of Florida would be eligible for
Federal funds to implement management actions that promote the
protection and recovery of Brickellia mosieri and Linum carteri var.
carteri. Information on our grant programs that are available to aid
species recovery can be found at: http://www.fws.gov/grants.
Although Brickellia mosieri and Linum carteri var. carteri are only
proposed for listing under the Act at this time, please let us know if
you are interested in participating in recovery efforts for these
plants. Additionally, we invite you to submit any new information on
these plants whenever it becomes available and any information you may
have for recovery planning purposes (see FOR FURTHER INFORMATION
CONTACT).
Federal agencies are required to confer with us informally on any
action that is likely to jeopardize the continued existence of a
species that is proposed for listing. Section 7(a)(4) requires Federal
agencies to confer with the Service on any action that is likely to
jeopardize the continued existence of a species proposed for listing or
result in destruction or adverse modification of proposed critical
habitat. If a species is listed subsequently, section 7(a)(2) requires
Federal agencies to ensure that activities they authorize, fund, or
carry out are not likely to jeopardize the continued existence of the
species or destroy or adversely modify its critical habitat. If a
Federal action may adversely affect a listed species or its critical
habitat, the responsible Federal agency must enter into formal
consultation with the Service.
Federal agency actions within these plants' habitat that may
require conference or consultation or both as described in the
preceding paragraph include, but are not limited to, the funding of,
carrying out, or issuance of permits for resource management
activities, development of facilities, road and trail construction,
recreational programs and any other landscape-altering activities on
Federal lands administered by the Department of Defense, National Park
Service, Fish and Wildlife Service, and U.S. Forest Service; or the
issuance of Federal permits under section 404 of the Clean Water Act
(33 U.S.C. 1251 et seq.) by the U.S. Army Corps of Engineers;
construction and management of gas pipeline and power line rights-of-
way by the Federal Energy Regulatory Commission; construction and
[[Page 61292]]
maintenance of roads or highways by the Federal Highway Administration;
and disaster relief efforts conducted by the Federal Emergency
Management Agency.
The Act and its implementing regulations set forth a series of
general prohibitions and exceptions that apply to endangered plants.
All prohibitions of section 9(a)(2) of the Act, implemented by 50 CFR
17.61, apply. These prohibitions, in part, make it illegal for any
person subject to the jurisdiction of the United States to import or
export, transport in interstate or foreign commerce in the course of a
commercial activity, sell or offer for sale in interstate or foreign
commerce, or remove and reduce the species to possession from areas
under Federal jurisdiction. In addition, for plants listed as an
endangered species, the Act prohibits the malicious damage or
destruction on areas under Federal jurisdiction and the removal,
cutting, digging up, or damaging or destroying of such plants in
knowing violation of any State law or regulation, including State
criminal trespass law. Certain exceptions to the prohibitions apply to
agents of the Service and State conservation agencies.
Preservation of native flora of Florida (Florida Statutes 581.185)
sections (3)(a) and (b) provide limited protection to species listed in
the State of Florida Regulated Plant Index including Brickellia mosieri
and Linum carteri var. carteri, as described under Factor D, The
Inadequacy of Existing Regulatory Mechanisms. Federal listing increases
protection for these plants by making violations of section 3 of the
Florida Statute punishable as a Federal offense under section 9 of the
Act. This provides increased protection from unauthorized collecting
and vandalism for the plants on State and private lands, where they
might not otherwise be protected by the Act, and increases the severity
of the penalty for unauthorized collection, vandalism, or trade in
these plants.
We may issue permits to carry out otherwise prohibited activities
involving endangered and threatened plant species under certain
circumstances. Regulations governing permits are codified at 50 CFR
17.62 for endangered plants, and at 50 CFR 17.72 for threatened plants.
With regard to endangered plants, a permit must be issued for
activities undertaken for scientific purposes or to enhance the
propagation or survival of the species.
The Service acknowledges that it cannot fully address some of the
natural threats facing Brickellia mosieri and Linum carteri var.
carteri (e.g., hurricanes, tropical storms) or even some of the other
significant, long-term threats (e.g., climatic changes, SLR). However,
through listing, we provide protection to the known populations and any
new population of these plants that may be discovered (see discussion
below). With listing, we can also influence Federal actions that may
potentially impact these plants (see discussion below); this is
especially valuable if either species is found at additional locations.
With this action, we are also better able to deter illicit collection
and trade.
Our policy, as published in the Federal Register on July 1, 1994
(59 FR 34272), is to identify to the maximum extent practicable at the
time a species is listed, those activities that would or would not
constitute a violation of section 9 of the Act. The intent of this
policy is to increase public awareness of the effect of a proposed
listing on proposed and ongoing activities within the range of species
proposed for listing. The following activities could potentially result
in a violation of section 9 of the Act; this list is not comprehensive:
(1) Import any such species into, or export any such species from,
the United States;
(2) Remove and reduce to possession any such species from areas
under Federal jurisdiction; maliciously damage or destroy any such
species on any such area; or remove, cut, dig up, or damage or destroy
any such species on any other area in knowing violation of any law or
regulation of any State or in the course of any violation of a State
criminal trespass law;
(3) Deliver, receive, carry, transport, or ship in interstate or
foreign commerce, by any means whatsoever and in the course of a
commercial activity, any such species;
(4) Sell or offer for sale in interstate or foreign commerce any
such species;
(5) Introduce any nonnative wildlife or plant species to the State
of Florida that compete with or prey upon Brickellia mosieri or Linum
carteri var. carteri;
(6) Release any unauthorized biological control agents that attack
any life stage of Brickellia mosieri or Linum carteri var. carteri; or
(7) Unauthorized manipulation or modification of the habitat of
Brickellia mosieri or Linum carteri var. carteri on Federal lands.
Questions regarding whether specific activities would constitute a
violation of section 9 of the Act should be directed to the Field
Supervisor of the Service's South Florida Ecological Services Office
(see FOR FURTHER INFORMATION CONTACT). Requests for copies of
regulations regarding listed species and inquiries about prohibitions
and permits should be addressed to the U.S. Fish and Wildlife Service,
Ecological Services Division, Endangered Species Permits, 1875 Century
Boulevard, Atlanta, GA 30345 (Phone 404-679-7140; Fax 404-679-7081).
If Brickellia mosieri and Linum carteri var. carteri are listed
under the Act, the State of Florida's Endangered Species Act (Florida
Statutes 581.185) is automatically invoked, which would also prohibit
take of these plants and encourage conservation by State government
agencies. Further, the State may enter into agreements with Federal
agencies to administer and manage any area required for the
conservation, management, enhancement, or protection of endangered
species (Florida Statutes 581.185). Funds for these activities could be
made available under section 6 of the Act (Cooperation with the
States). Thus, the Federal protection afforded to these plants by
listing them as endangered species would be reinforced and supplemented
by protection under State law.
Peer Review
In accordance with our joint policy on peer review published in the
Federal Register on July 1, 1994 (59 FR 34270), we will seek the expert
opinions of at least three appropriate and independent specialists
regarding this proposed rule. The purpose of peer review is to ensure
that our proposed listing and critical habitat designation are based on
scientifically sound data, assumptions, and analyses. We will invite
these peer reviewers to comment during this public comment period on
our specific proposed rule.
We will consider all comments and information we receive during
this comment period on this proposed rule during our preparation of a
final determination. Accordingly, the final decision may differ from
this proposal.
Public Hearings
Section 4(b)(5) of the Act provides for one or more public hearings
on this proposal, if requested. Requests must be received within 45
days after the date of publication of this proposed rule in the Federal
Register. Such requests must be sent to the address shown in FOR
FURTHER INFORMATION CONTACT. We will schedule public hearings on this
proposal, if any are requested, and announce the dates, times, and
places of those hearings, as well as how to obtain reasonable
accommodations, in the Federal Register and local newspapers at least
15 days before the hearing.
[[Page 61293]]
Required Determinations
Clarity of the Rule
We are required by Executive Orders 12866 and 12988 and by the
Presidential Memorandum of June 1, 1998, to write all rules in plain
language. This means that each rule we publish must:
(1) Be logically organized;
(2) Use the active voice to address readers directly;
(3) Use clear language rather than jargon;
(4) Be divided into short sections and sentences; and
(5) Use lists and tables wherever possible.
If you feel that we have not met these requirements, send us
comments by one of the methods listed in ADDRESSES. To better help us
revise the rule, your comments should be as specific as possible. For
example, you should tell us the numbers of the sections or paragraphs
that are unclearly written, which sections or sentences are too long,
the sections where you feel lists or tables would be useful, etc.
Paperwork Reduction Act of 1995 (44 U.S.C. 3501 et seq.)
This rule does not contain any new collections of information that
require approval by OMB under the Paperwork Reduction Act of 1995 (44
U.S.C. 3501 et seq.). This rule will not impose recordkeeping or
reporting requirements on State or local governments, individuals,
businesses, or organizations. An agency may not conduct or sponsor, and
a person is not required to respond to, a collection of information
unless it displays a currently valid OMB control number.
National Environmental Policy Act (42 U.S.C. 4321 et seq.)
We have determined that environmental assessments and environmental
impact statements, as defined under the authority of the National
Environmental Policy Act, need not be prepared in connection with
listing a species as endangered or threatened under the Act. We
published a notice outlining our reasons for this determination in the
Federal Register on October 25, 1983 (48 FR 49244).
References Cited
A complete list of references cited in this rulemaking is available
on the Internet at http://www.regulations.gov and upon request from the
South Florida Ecological Services Office (see FOR FURTHER INFORMATION
CONTACT).
Authors
The primary authors of this package are the staff members of the
South Florida Ecological Services Field Office.
List of Subjects in 50 CFR Part 17
Endangered and threatened species, Exports, Imports, Reporting and
recordkeeping requirements, Transportation.
Proposed Regulation Promulgation
Accordingly, we propose to amend part 17, subchapter B of chapter
I, title 50 of the Code of Federal Regulations, as set forth below:
PART 17--[AMENDED]
0
1. The authority citation for part 17 continues to read as follows:
Authority: 16 U.S.C. 1361-1407; 1531-1544; 4201-4245; unless
otherwise noted.
0
2. Amend Sec. 17.12(h) by adding entries for ``Brickellia mosieri''
and ``Linum carteri var. carteri'', in alphabetical order under
Flowering Plants, to the List of Endangered and Threatened Plants, to
read as follows:
Sec. 17.11 Endangered and threatened wildlife.
* * * * *
(h) * * *
--------------------------------------------------------------------------------------------------------------------------------------------------------
Species
------------------------------------------------------ Historical range Family Status When listed Critical Special
Scientific name Common name habitat rules
--------------------------------------------------------------------------------------------------------------------------------------------------------
Flowering Plants
* * * * * * *
Brickellia mosieri.............. Brickell-bush, U.S.A. (FL)........ Asteraceae......... E ........... NA NA
Florida.
* * * * * * *
Linum carteri var. carteri...... Flax, Carter's U.S.A. (FL)........ Linaceae........... E ........... NA NA
small-flowered.
* * * * * * *
--------------------------------------------------------------------------------------------------------------------------------------------------------
* * * * *
Dated: September 25, 2013.
Rowan W. Gould,
Acting Director, U.S. Fish and Wildlife Service.
[FR Doc. 2013-24173 Filed 10-2-13; 8:45 am]
BILLING CODE 4310-55-P